Will this be Nintendo switch compatible?

It isn't hard to say. The answer is no. Power PC and NVIDIA Tegra are completely different architectures so Backwards Compatibility is impossible. Additionally the Switch isn't powerful enough to emulate the Wii U. As for Xbox One, it's "Backwards Compatibility" is actually emulation, which is possible because the Xbox One is ~10 times more powerful than the 360. The Switch is only ~3 times more powerful than the Wii U.

Secondly, this deal is now sold out.

The Wii was BC with GameCube and the Wii U was BC with Wii + GC so perhaps Nintendo can find a way to make NS compat with Wii U. However, if it's not then it's not a big deal either.

The reason for that was that the GameCube, Wii and Wii U all used the same architecture, Power PC. Switch has changed architecture to NVIDIA Tegra.

I get that but Nintendo tends to be different from the rest and surprise us.

Nintendo can be different in design, aims, methodologies but they cannot just say 2+2=5 and make it be so which is analogous to what you are suggesting.

I'm not saying Nintendo wouldn't do it. I'm saying that it is impossible.

Additionally, if the Switch were BC with the Wii U then why, exactly would they port Wii U games to it? That's all in addition to the disc issue.

We have the technology issue which already makes BC impossible and we also have the lack of a disk drive and the fact that there is no reason that Nintendo would waste resources porting games from Wii U -> Switch if it could already play them.

(And in case you're about to say "Graphical Upgrades", a console 3 times more powerful will not get significant enough Graphical Upgrades to bother wasting resources on ports.)

Edit: Nintendo have confirmed that it will not be backwards compatible with Wii U or 3DS.

http://www.perfectly-nintendo.com/nintendo-switch-nintendo-confirms-lack-retro-compatiblity-note-battery-life/

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