Yes, overfilling can cause transmission problems. A half quart or so over is not a problem. Two quarts over could very well be.
When transmission fluid is overfilled it can turn into “frothing”; which means the fluid is being churned into a mix of fluid and bubbles. That in turn affects various pressures inside the transmission including the clutch packs and soon the transmission will fail.
Just my 2 cents, but if the transmission has been untouched since it was replaced and was 2 quarts over I would say that the dealer should pony up on this repair and unemploy the guy who done it.
This will likely come to push and shove so you might consider contacting the Nissan regional office and drag them into it. Maybe they will step in and replace it again under what is referred to as a “Good Will” warranty.
Hope that helps and good luck.