The A9X is probably more powerful than a Wii U, the Tegra X1 is almost certainly, neither are expensive chips.
People here really don't understand how powerful modern affordable mobile chips are.
The Vita is ancient, and that was only $250 almost five years ago.
The chip isn't what's expensive ... for a portable it's the LCD screen that's the no.1 cost ... if you're willing to accept a decent/low cost screen like a 1280x720 display at 6-6.5 inches that's easy enough to sell by this fall for $200-$250.