Fast Racing Neo on Wii U is 720p, but it's a reconstructed 720p, where certain elements in the scene are rendered at variable resolutions. So it's less than full fat 720p, but a lot better than 540p. They may be using a similar technique here though, so the thread title may not be accurate. We also don't know if it's simply a remaster, as the amount of tracks that are new hasn't been confirmed. It could be a new game that simply features some retro tracks from FRN, like the recent Mario Kart entries.
At any rate, ever since the GBA, Shin'en have always managed to extract some of the best graphics from Nintendo hardware, and it looks like Switch will be no different.
Some more gameplay with commentary from the game's director, who confirms 60fps in 2-player splitscreen, and says the Switch is easy to develop for:
