At the most, I'd hope that it's a wearing U joint that you could be hearing, but it could be a ton of things. After going through and doing a new lifts, a lot of new noises of older, worn parts can come out, but that's not to say a failure of anything is immanent. A 2" lift is pretty mild, so I wouldn't be too concerned about anything being too overly stressed. A few things to research and check out on your truck:
-Did you do any other front end work/component replacement? Lower ball joints, outer tie rods, etc? Not necessarily cause of the noise, but depending on your mileage, good to do all that stuff while you're in there.
-Have you greased any of the driveshaft grease zerks? Simple, but it'd be nice if this was the cause of your issue.
This would be the first place I'd start
-It's not super common, but maybe it could be a U joint or the spiders? Again, try greasing first
-Check/change your rear diff fluid, and make sure you do it on as flat of a surface as possible.
There are a few good tips in this thread
Again, a 2" lift is fairly mild, in my opinion, so I wouldn't be as concerned with all of the supporting mods, though a panhard bar raise/drop kit from Eimkeith might make the truck less squirrely and handle better in the corners, if you've noticed a big change since the lift. Also, I assume you got a good alignment after? I paid for the unlimited Firestone alignment when I first lifted, and they were absolute garbage. Went to a local shop and they had it dialed in perfectly.
My brother did the ToyTec superflex lift in spring 2020, and he's just now finished chasing down all the noises...