I'm quite inclined to believe that NX's first pokemon game will be a battle game ala Stadium which connects with your pokemon go account. There was a rumour saying that Pokemon would be on NX in the first 6months (as you've said it'd be dumb not to capitalise on Go) yet I doubt that they'll release another full length RPG right after Sun and Moon has just come out.
I think that would be a great idea. It would solve the simplistic battle mechanics from Go. But also mind that they could just plan to port Sun and Moon to NX.
Yeah, I thought they would have announced it for NX like they did Zelda but I guess we'll find out in a few weeks.