I have a 2014 Sentra with 100k miles. 2 days ago I was driving on the freeway when all of a sudden the car wouldn't accelerate and the speed slowly dropped. Had no warning light on at all. I pulled over turned the car off for about 2 minutes. I turned the car back on and it has been driving fine since. What could have caused that episode???

Could have been crud in the MAF, moisture in a tail lamp, bad brake lamp switch, or an overheated CVT going into self-protection. If it was the MAF or the brake switch there will likely be no evidence, but if it does it again, take note if the third brake lamp is on even though you're not on the brake. If it's a leaky tail lamp then there may be a P0705 in the TCM if the reverse lamp circuit was falsing, probably nothing if it was the brake lamp circuit. Vis the CVT, have a dealer (or someone with a high-end scanner like a SnapOn Solus) check the values for CVT-A and CVT-B. Those are the overheat counts in the TCM. If they're above zero then your tranny has had at least one overheat episode, probably from worn-out fluid if you've never changed it.

CVT fluid was replaced by the dealer 2 years ago

Probably not the CVT then. Wet tail lamps or a sticky brake switch are probably your most likely culprits. The TCM monitors both the brake and reverse circuits, it will refuse to accelerate forward if it sees either one of them. A low-grade short circuit created by moisture in a tail lamp can cross-up the brake and reverse signals or make the brakes appear to be on when they aren't, and obviously a sticky brake pedal switch can cause the lamps to be on for no reason. A crossed reverse circuit will generally cause a P0705 because the TCM sees the car in forward gear with reverse lamps at the same time. It will blame the Range Switch and not the lamps, but Nissan Range Switches are very robust and rarely fail, the problem is almost always wet lamps.

Primodlt, were you able to fix the problem?