Emily Rogers Rumour: There's a lot of Wii U ports coming to NX

[TheMagicMax]

Not surprising at all. Some of the ported games will probably sell good numbers again.
Sm4sh and Zelda seem obvious. I would also really like to see a ported version of Xenoblade X with improved resolution, AA and less pop-up. Bayonetta 2 would also make sense if Nintendo wants to make a sequel.
Aside from that, Splatoon probably and if there is a controller like the gamepad - Super Mario Maker.

I don't expect Mario Kart 8 to be ported since im pretty sure that the next entry will be released in 2017.