Coolant flush is irrelevant to the problem you cite. NOT justified by that problem. You might be ready for a coolant flush, but you can also do it yourself. It has nothing at all to do with the transmission.
CVT fluid should ONLY be changed if they do the factory-approved analysis of CVT fluid and that analysis determines that there is a problem with the fluid. DO NOT pay for a fluid change unless the analysis is done and confirms a problem (it won't). There are a few threads here which discuss the factory test for CVT fluid wear.
The only other reason for a CVT fluid change would be if there is contamination from some other fluid, and that's extremely unlikely.
I agreed to do the the transmission and coolant flush because the service guy said that it may cause the transmission problem. If they ultimately have to replace the CVT, I am assuming that transmission and coolant flush is going to be covered. I think they're going to pull something shady here.
I called Nissan this morning. They told me to follow up with them over the next couple of days.
Nissan responded to my call the other day and they told me to wait until the dealer further clarifies the problem. I am concerned that they will not push the dealer to replace the CVT and the cost of the transmission and coolant flush (which the dealer claimed to may have cause the CVT problem) under warranty.
I ended paying for for the transmission flush and coolant service. I mentioned how this should be covered by the warranty, but I didn't really push. I can tell that the service guy was being dishonest with me; he didn't really look me in the eye, but I decided not to bother.
I notice that they did double-bill me for the transmission fluid and I will call Nissan Assist on Monday.