Makes sense for Microsoft. I've said it on more than one occasion in "Nintendo should make games for PS/Xbox" threads that the other way around is more likely, but people didn't want to believe it because they only saw Wii U sales, not all the companies' financials and their goals in gaming.
Microsoft has been moving away from Xbox consoles as their focus for a while now. They've ceased to make Xbox exclusives by releasing their games on PC as well. They have been moving toward games as a service, so the hardware loses importance because a bigger reach can be attained by making the service available on as many platforms as possible.
Nintendo, on the other hand, won't put their games on Xbox in return. They believe in their core business as much as always, and exclusive games are key to selling as many consoles as possible. There won't be any 1-for-1 trades in this partnership, because Microsoft is a third party for Nintendo as opposed to two console manufacturers working together.