The best way to get Nintendo, or any other platform holder even considering implementing Construct support,
is to start using Construct to produce the type, and quality, of games that they want on their systems.
...
Then they will be calling Scirra...
This has not really anything to do with Scirra/Construct.
It is having official support for HTML5. (Switch actually already has HTML5 support, but not officially, but they have a built in browser which can run games! But the browser seems to be for posting Facebook stuff mostly...)
They need to open up the Web Framework also for Switch (and not only WiiU), so you can release/install/play HTML5 games in Switch, with official support. WebGL
It has nothing to do with Scirra or Construct really, if the Web Framework will be open then it will be possible to release stuff to it