Holy ****, I missed this.Nope, can’t use a junkyard one. Every CVT is different enough that the computer will go into limp mode if you put in a different transmission without reprogramming it with the parameters specific to that exact transmission, so unless you are going to tow the car from the junkyard to the dealership to have the programming extracted to swap into your car after you swap the trans, any used one is just a paperweight. When you buy a new or rebuilt one, it comes with a CD that has the programming for that particular trans, which has to be loaded with a dealer scan tool.
I see why people are trying to get "Right to Repair" laws in place; this is one that you're fucked without the dealer.
Another reason never to buy a Nissan.