Afaik there is no Dynarec for PPC architecture (which the Wii U is) for any of the N64 emulators available at the moment.
The most famous one would be Mupen64, and I believe that one doesn't have a Dynarec for PPC.
So in order to have one, we would first need to get the dynarec for Mupen64 ported over to PPC, and then we could hopefully get it to build for Wii U in RetroArch as a core.
Out of that, there is not many options, you could try to inject N64 games via N64 VC injection, or perhaps play them in vWii with Not64.
Another option would be to try to port Not64 to Wii U; since the Wii was also PPC, but I don't know how much of a hassle that would be.