The two projects are currently at least a year apart (WDW is aiming for Star Wars to open in the summer period of 2019).
Nintendo isn't the counter programming to Star Wars, it's the solution to Fantasyland and animated branding. It is Universal finally trying to plug a demo gap (a family brand) they have had middling success with.
Yes millennials and the tail end of Gen X love Nintendo, but they love a lot of Universal properties. This is a big move for them to really give something of value to a family with a dad, a tween and a four year old to enjoy something all together.
Which is honestly a bigger move than countering Star Wars, it's to counter the one clear demo lead Disney has.