I don't know if this post has been made before, but I thought I should point out something that should be obvious but may not be for some.
With regards to the current generation of consoles (or even electronic devices), the wii u is an anomoly. It is the only console to retain the power pc architecture over the x86 architecture. With the introduction of the NX, we can gaurantee that it will contain x86 architecture (and if it doesn't, it will have near 0 third party support) to match the ps4 and the xbox one. The problem with this is that the current wii u games would have to manually be ported in order to play them on the NX (similar to how the xbox one is currently doing backwards compatibility for the xbox 360). Either that, or an emulator would have to be built (using what the NX has) to emulate those wii u games. However, none of these options seem practical for the NX (they want it out soon and at a reasonable price) which is why it would hold to reason that the NX would not be backwards compatible.
Just thought I would let people know so they don't get their hopes up.