Go to the Edmunds.com webpage and click on “tips and advice” button. Then click on the car maintenance button. Here is the specific site:
Enter your year make and model and the mileage and your zip code. Depending on your mileage, you will see exactly what fluids need to be changed and when. CVT fluid is expensive. The Nissan brand goes for 25 bucks a quart. Redline sells compatible fluid for 15 bucks a quart. I would probably err on the side of safety and change the fluid every 50K miles even if they tell you it is good for 75-100K miles. It's still cheaper to change the fluid than a new transmission!