It won't be just a portable that inexplicably gets a "boost" if it just so happens to connect to a competitors console. That would cause developers to have to develop two games for one system - or one very high end game that utilizes low LOD when it is mobile only. Not worth the investment for those who will only use the mobile unit.
NX is a codename used to describe a NINTENDO family of hardware units that share data with each other with each utilizing a similar architecture for ease of cross hardware game and app development. The mobile system can share the "same" game data with the "beefy" home based unit allowing for high fidelity gaming at home and the "same" game (using shared saved data), but at a lower fidelity while on the road. Actually surprised no one has done this before.
Other Nintendo hardware units as well as some existing and future competing hardware units (phones, tablets, etc.) will join the home console and mobile unit to run Nintendo software to be called cohesively, the NX platform. Still just a codename. Pretty ambitious stuff.
Interesting concept.
Am I the only one who envisioned the NX as a handheld device that can be connected to a TV using streaming technology? The NX would cost more than an average handheld because of its ability to stream HD gaming with performances similar to last gen consoles to a TV. Its selling point would be that you can play the games wherever you like, also on your TV. I'm struggling to explain this idea, but I hope it's understandable.