2010 Nissan Altima tire pressure light remains on

the tire pressure light is still on in my 2010 Nissan Altima after I have purchased new tires, what should I do

There might be a reset procedure or your sensors need replacing. If they are the original sensors probably should have been replace when the new tires were mounted.

First, I’d actually check the tires and make sure they all have the recommended pressure. If one is low, air it up and keep an eye on it. If not, then @Purebred is correct and you probably have a bad pressure sensor.