I believe the next Nintendo home console will come in 2017-2018 and will be 50% more powerful than the PS4, this will be a full 2 years before Sony/Microsoft release another console. It will come with a tablet controller similar to Wii U but it will be able to be online anywhere you go and not need to be tethered to the console. With cloud technology this will be not difficult to achieve.
As for their handheld console I'm guessing something similar with graphics abilities slightly better than the Wii...







