When the game launched on Steam last year, we made a couple of posts on Reddit to market the game, usually Godot, Linux and other FOSS related communities, or maybe some Brazillian communities as well. A guy from Pineapple Works contacted me there asking if we would like the game ported. They handled the porting process completely. As far as I know, you need contract with Nintendo, in which they send you a dev kit and their SDK and you're under NDA to not share it. They basically made their own Godot export template, and maintain a Godot branch as well. You can contact them if you want more information!