There is what looks like a dipstick tube with a black plastic locking cap on it in the engine bay, towards the engine air filter box. Nissan refers to them as a charge tube. It's where you add fluid. There's no stick attached to the cap.
Fluid drains and level checks are done under the vehicle. The transmission pan has a drain plug and off to the side of the pan on the transmission case is the level check plug.
Fluid level is checked with the engine idling in park with the vehicle on a level surface and the CVT fluid within a specific temperature range. I'd have to look it up, but I believe it's around 113F. Cooler than normal operating temps.
I've done many drain/fills on Nissan CVTs. I drain them cold. Measure the amount that came out and add that exact amount back in. After several drain/fills if I'm feeling ambitious, I'll check level using an IR temperature gun to measure the fluid temp at the pan. It's not the right way to do it, but it's in the ballpark.
Unless you purchased an extended warranty with your 2016, or it's a CPO with 7yrs/100K miles, the powertrain warranty is 5yrs/60K miles. You've got about a year and 9K miles to go.
There is actually a special service tool for checking the fluid level now that dealers were sent, but generally, the only way to check it is to remove the check plug, pump a liter in, then wait and see if it starts leaking out. For a drain and fill, you will be putting in around 5 liters.
Transmission temp needs to be between 35-45c. If you took out 5 liters, put 6 in. Start it up let it run til the trans temp is around 32C, at that point start getting ready to pull the check plug. Once you see 34-35 pull it and let it drain out til its a very slow thin dribble then put it back in and thats it. If you overfill it too much it will get past 45C before its drained out to the correct level, which will result in a lower than spec fluid level when cold, so ill usually pull it at around 32. The reason for ovefilling it, is it eliminates the time consuming proceed to adding fluid then back and forth this way your under the car once and thats it.