The transmission is "fill for life" as per factory recommendations. You can have it serviced(drain/flush and refill) whenever you want. There is no provisions to stipulate a trans fluid change for warrenty purposes and such. There is a oil life monitor also. Which will trip a code when Trans fluid is close to end of life. These calculations are done by monitoring driver habits. Just like many cars do for engine oil changes. They monitor driver habits and calculate when engine oil change is nessasary. As long as it don't flat out fail

I'm sure the special Nissan fluid for this would be no less than $15-$20 a quart. And the filter is not replaceable unless you split the transmission case in half.