I wouldn't really call it a Nintendo game on PC.
Valhalla owns the rights to the IP after THQ went under. Nintendo merely gave them money to make it. Valhalla can do what they want afterwards, including a F2P multiplayer-only PC version.
That's not how it works. You could never see W101 or Bayo2 on other platforms despite the fact Nintendo doesn't own the IP.
Nintendo must have explicitly granted the PC version, or Vallhalla had a favorable contract from the get go.
Edit - It says right in the press release:
"By prior agreement with Nintendo, Valhalla has developed the free-to-play PC
exclusive online game “Devil’s Third Online.”
Nintendo okayed it, not because the IP is owned by Valhalla.
Also:
"To spread “Devil’s Third” around the world,
this game service will run from September 2015 onwards, in various regions around the
world following the release of the Wii U version in each region."
Timed WiiU exclusive.
Edit #2- apparently W101 is owned by Nintendo. My point still stands with Bayo 2.