I would hope the handheld is around the WiiU's power, or at the very least X360's.
Nintendo's handhelds seem to be around the power of two generations prior (GBA-SNES, DS-N64, 3DS-NGC). A handheld around the WiiU power would be a big jump.
e=mc^2
Gaming on: PS4 Pro, Switch, SNES Mini, Wii U, PC (i5-7400, GTX 1060)