Not a promise, though
"Without making any promises, I think it will be likely that the game ends up on the Wii U. I have been in touch with a publisher that is interested in putting it on that console, and I’d be more than interested in seeing that happen!"
I would love to see this game on a Nintendo console as an eShop game. If the Wii U can get ahead with a strong eShop showing with some quality indies, it will easily be my favorite console of the generation. Check out the rest of the interview too -- it's got some good chat about 3D platformers and collectathons.
As of now, A Hat in Time is slated for PC and Mac, and you can vote for it on Steam Greenlight.