It depends on what kind of game we're talking about. If they announce something like Disgaea 6, which would be further down the line (potentially second half of 2018 / end of first half at earliest), given what Niikawa said recently, that would be a PS4/Switch game. I suppose ports wouldn't need that much time to be worked on compared to new games: here, I'm referring to not just Penny-Punching Money / TL5M (which, honestly, I don't see releasing in Japan for one specific reason: their original sales were so low that NIS probably don't see the point in re-releasing them in Japan on a different system), but even to stuff like ports of older Disgaea (one of the other things mentioned by Nikawa in the recent AMA, depending on Disgaea 5's sales...and we know how they're going).
Still, even if I know (given what you already said) NIS (and not just NISA) is going to support Switch in the future thanks to the eye-opening Disgaea 5's result, I'd just like to see something already, even if it's not that major (relatively for them, of course)