Completely different car but when I searched the internet for CVT fluid change on my
2015 Versa Note (Take this with a grain of salt because it came off the internet)
There is no drain plug (on the Versa) thus they have to add a fitting to drain the fluid.
It needs to be Nissan trans fluid.
Some say you have to run the engine while changing the fluid.
The dealer quoted me $220 so I am probably going to do that (but you know they will find other things wrong once they get under the car)
Maybe check youtube for 2015 Nissan Altima CVT fluid change?