My Non-smart TV is put up on the wall without any outlets nearby for something like a nvidia shield or nexus player.
I really want to stream games on something that's connected only via HDMI and powered from the TV's usb.
What would be the route to go?
Sorry, I don't think that fits the power requirements of any smart tv device. What you could do is get a power strip and plug it into the same power outlets your tv is plugged into , and use any of the devices you mentioned earlier.