There isn't a lot of full-electric CUV roaming around, so Nissan still has time to develop their own, while selling the Leaf to generate interest and profit. Though I do agree with Nissan releasing it in other countries first in order to iron out any problems before releasing it in markets that are less forgiving. Just takes a few lemons to tank a model.
Well the Chevy Bolt is in a way like a CUV so considering that Nissan is behind. Not only that but the Bolt's platform was likely developed with a bigger EV in mind. So GM has been on top of the game for many years already, meanwhile we haven't seen much from Nissan.