My wife did recruiting for the university where we were both employed and put a lot of miles on vehicles from the university’s fleet. She found the Honda Civic Hybrid most uncomfortable. She found the Ford Taurus the most comfortable, although the Chevrolet Malibu and Impala and even the Dodge Charger were acceptable.
I still think that the OP’s wife would be better off in a larger car. The ride would be smoother and the seats would probably be more comfortable.
We once owned 1985 Ford Tempo that we purchased as a new car. It was economical to operate and was as reliable as booze in a bar. After three years, we decided we wanted something that had a smoother ride, so we traded it for a 1988 Ford Taurus. The Tempo was the only vehicle I traded before the odometer showed 50,000 miles. I never regretted going to a larger car.
Your tire store didn’t do you any favors. Your tires did not rate very well on Tirerack.com, the less expensive Continental PureContact did much better especially in comfort. But there are worse.
You did not say what sub model you have, I.e. SL or SR. The SR will have a stiffer suspension than the SL but if the struts are worn out, it won’t make any difference which model you have.
You could replace the struts yourself IF you get the KYB strut+ assembly. They are $156 on tirerack.com and because they are fully assembled, you do not need a spring compressor. You also gat all new parts. If you have the SR model, you could order the assembly for the SL model, they won’t be as stiff.
You will need a safe place to work and at least one jack stand if you do only one corner at a time. Do not rely on your jack As soon as your done, take the vehicle to a shop for a front end alignment before you wear out the tires.
I’ve ridden in a friend’s Sentra a few times and the only cars I’ve ridden in with a worse ride were a 2007 Toyota Yaris and a fully restored 1923 Ford model T.
In my humble opinion your cheapest, easiest option for the ride you describe would be an Urban Warrior, something like the cabbies used to drive. A used Ford LTD or similar, samples of which you can easily find previously owned by Grandparents in the world outside of NYC.
Soft ride, all the room in the world for her “office” (or you could park it in Manhattan and rent it as a luxury efficiency or on BNB for $2,000/month) and virtually indestructible.
Lousy gas mileage but you’re in NYC, not North Dakota, so how far are you going to drive it?
Doesn’t look pretty but if you ever street park, after 15 minutes even a Ferrari won’t be pretty and it’ll be strong enough to push even the largest SUV “a few inches” to get into that space.
And it’ll be cheap enough that you don’t need collision insurance.
On the other hand if you can afford a space in a parking garage in NYC (not the outlying Boroughs), DC, SF, etc., then what the heck, go for the Benz, Rolls or whatever!
@old_mopar_guy. I am rather insensitive to the ride of a car. The comfort of the seat is more important to me. The Sentra that my research partner and I took on a 600 mile round trip to present at a conference was ten or more years ago.
However, if the OP’s Sentra is uncomfortable for his wife, it’s time to get something else. I don’t think new struts, or going to a different tire and rim size is going to make enough difference to be worth the expense.
Also, the vehicles I have driven with the continuously variable transmission seem noisy to me in city driving. The Sentra I drove some years back reminded me of the early 1950s Chevrolet PowerGlide or Buick Dynaflow. While I am rather insensitive to riding quality of a car, I am sensitive to noise. In my college years, I didn’t have a car and rode a bus line that ran Flxible buses powered by straight 8 Buick engines. These buses had a high pitched whine and my ears would be ringing for hours after I got off the bus from the 50 mile ride. I also found it tiring to watch television in the days of the black and white sets with the cathode ray picture tube. There was always a buzz around 18,000 hz that I found fatiguing. Maybe the OP is overlooking the noise factor in the Sentra. Consumer Reports used to measure the noise level of the test cars in sones at 60 mph on the highway. CR has abandoned this measurement which I consider important.
ANYONE driving around all day in Manhattan or the Boroughs is going to be exhausted, traffic, roads, & other drivers are all obscene. Does not matter if you’re driving a Sentra or a Lexus 460 !! Still, somewhat larger car will be helpful… of course PARKING is always a problem, which may be why you bought a small car.
If she’s a visting nurse, she’s either an employee, and getting mileage reimbursement, or an independent contractor, and writing off mileage on your taxes. Either way, you need to balance her health & energy, (and Safety! small cars not as safe as larger ones in a collision - basic physics) against $$ wealth; As I used to put it, when I drove around daily for business, You need a good horse.
I’d suggest swapping this car for a similar mileage, but earlier year Camry LE 4-cyl, reliable, and reasonably cheap on gasoline. The Crown Victoria idea is also good, but, it’s a loooong car, hard to find on-street parking in City.
Good Luck !!
If swapping the car, I would rather imagine some mid-sized corssover/SUV like Hodna CR-V or Mazda CX-30/CX-5 or so for NYC use.
A barge like Camry or Crown Victoria?? Nop 
Those look like really nice rims… in a city the size of NYC maybe you could find a set of Nissan 16" steel rims that are correct for your car through craigslist and put new tires on those. When you’ve got it all sorted out I think you could sell your current rims for at least $100/ea if you take your time and have a place to store a stack of wheels (maybe that’s the hardest part).
I think this would make some difference in ride comfort, at the expense of looks though.
I had a couple of 2019 rental cars recently. A Nissan Sentra. It had a fairly stiff ride which I prefer. It could have been an SR. Last week I had a Toyota Corolla. By then I had read this post. It had a noticeably softer ride so I checked the tire size. 205/55/16R.
The car is 6 years old and the wife has likely acclimated herself to the current ride. With the addition of new shocks/struts she will likely find the new ride to be even stiffer than the old and you’re back at square one. If the car has 17" wheels then going to 16s and a higher profile tire would help.
It would be difficult for me to get enthused about wading into struts or new wheels on a 6 year old Sentra. Might be worth it if you’re keeping the car for the long term.
my elder daughter Altima came from NYC and by 68K miles it had struts which were shot, then checked for survivors and then shot again
really, car was riding like a playground bouncy horse when we bought it
I replaced all 4 struts with KYB (along with one shot stabilizer link) and it made a hell lot of difference on the ride
considering I did replacement myself and only got car for alignment into the shop, my total was under $400
So sorry to hear your daughter couldn’t strut 
but more seriously potholes are just the start of a car in an urban environment.
In my own daughter’s case, it was the rear suspension that really went through hell and enough tires blown that I started to suspect collusion between the road crews and the tire dealers but that paled besides the bodywork from downtown parking. The worst was from the “mystery truck” that bent the front bumper and hood while she was parked but the strangest was the roof dent from a padlock.
Seriously, that car came back looking like a whipped puppy and it was the same for all their friends.
So I’m sticking with my suggestion of that good old Detroit Iron; the older and bigger the better.
Rides, steers and handles like a Boat but smooth riding, tough enough to handle the toughest environment and cheap enough to avoid the need for Comprehensive coverage that looks like the National debt.
And hey, with sea levels rising and NYC being an island, being a “barge” may come in handy.
I’d be somewhat hesitant to recommend that particular brand for one rather glaring reason . . .
The ride height will probably be noticeably higher, versus the old struts
The ride itself is fine, but the gap between the tires and the fender is noticeably higher after the install
Monroe also has similar units . . . struts, coil spring and mounts, all pre-assembled. They’re easier to locate, the ride is fine and the ride height won’t change
Is this warning about the full assemblies or “bare” KYB struts in particular?
Myself, I replaced OEM with KYB on 3 Nissans (2 Altimas and 1 Pathfinder) and never had this issue, but I bought struts only, not full assemblies.
its a warning about the full assemblies
I might add I’m not the only one that’s mentioned this
Another regular also mentioned a rather noticeable increase in height . . . might have been @bing . . . and he said he had to reinstall the old coil springs to bring it back down to the previous height
thanks for the tip… I kinda missed the earlier warnings here
myself, I hate disposing of perfectly good OEM springs and other parts of assemblies, so I’m buying “bare” struts and rubber inserts what go under springs, once you are there, it is stupid not to replace proactively
In spite of the fact that the kyb strut + assemblies resulted in a higher ride height . . . I still feel that, generally speaking, it’s smarter to install a complete assembly
Why is that . . . ?
One time I replaced just the struts and reused everything else . . . a few months later, I had to go back and replace some mounts
Another time I replaced just struts and reused everything else . . . a few months later, I had to go back and replace broken coil springs
So those old parts that you’re thinking of reusing might not be “perfectly good” after all
Considering its New York City with all the potholes, a small increase in ride height could be a good thing, more spring travel to absorb the larger bumps.
I could not recommend just replacing the struts only unless the OP was an experienced mechanic as using a spring compressor can be dangerous to a novice.
It occurs to me that a 50 sidewall tire that is overinflated would provide a very hard ride. I suspect your tires might be way over the proper pressure.
As someone mentioned the 16’’ option for your vehicle 205 55 16 would be better as would a 15’’ option with 205 60 15 which would give you the softest ride.
For the past 10 years I used 17’’ on my Nissan X trail, and I just recently had a chance to try the 16’’ factory size, and all I can say is that it is noticeably smoother over cracked roads with 215 65 16 tires as compared to 215 60 17.
Regarding your wife’s preference for new stylish rims, that is what it is mainly-- fashion. Larger wheels with thinner rubber are mainly a look, in a few cases they will improve the handling, but in no situation will it improve the ride quality.