We have information on Smash NX??
Same rumor as last time. Bandai-Namco is developing it. That's it. We don't know if it's a port or all new game either. With the controllers confirmed to not have touch screen, it would have to be a changed-up port in some way. As I said before, both Smash 4 versions require a touch screen to play fully. Something would be changed. It may not be much, of course, but who knows what'll happen.
Of course, if it's an all new game, it could be quite interesting. But that also means the roster is likely going to be changed a bit. If only due to renewing copyrights and such for characters like Cloud, where Square-Enix is stingy(that said, if FFVIIr is coming to Switch, they could jump at the chance for promotional purposes), and if Sakurai isn't actually involved, who knows what could happen. That means his "rules" aren't there. Albeit, as I said as well, I think he is involved, but we won't know till the next Smash is announced and/or more information is given beyond a rumor.