Nintendo X

You are right but honestly NX sounds nice but knowing Nintendo some doofus will come up with something stupid and short that makes people scratch their heads.

Nintendo Not Explained (yet)!

NINTENDO WAVE

I really like Nintendo Fusion.

Wii R

It won't be Nintendo Cross, it is too religious sounding.

Nintendo Xeno. And it becomes a series of sorts like xeno 1, xeno 2 and xeno 3rd etc. Xeno name would sound cool and mysterious.

Nintendo Fusion sounds nice. Explains the concept of the console, it's catchy to the ears and it's not overly complicated. It works on so many levels.

"NX" probably doesn't have any meaning. Kimishima himself once said that he doesn't know where the codename came from. So it's probably another Nitro or Dolphin. I expect it to have a name that has nothing to do with its codename.