What's working for Nintendo right now is taking popular genres but putting their own spin on it.
Zelda: BotW takes on the popular open-world RPG genre.
Splatoon the online shooter.
ARMS looks like a take on the 1-on-1 arena fighter.
Nintendo should do more of that. Look at genres that are popular to today's audiences and make it Nintendo-like, in that process the game becomes unique and different anyway because no other studio approaches design like Nintendo does.
Stay away from 2D platformers and party games I would say. Too much of that, a few 2D platformers are OK, but too many like the Wii U was a problem.