I doubt the NX will get backwards compatibility with the Wii U. Even if just adding Espresso is dirt cheap they would have the issue of having to include every single feature of their custom Latte GPU in their new custom APU they order from AMD.
I personally find NX release of Zelda U a travesty as the Wii U would not have its exclusive Zelda. They shouldn't even remaster the game until the NX successor is released. But a NX port is very likely.







