Question: how to hook up nintendo to vizio smart tv?
Answer: Locate the Audio/Video inputs on the back of the TV.
Place the yellow end of the AV cable into the Video "in" on the back of the TV. Connect the white or red end of the cable to Audio "in" ("left" or "mono"). ... 
On the other end of the AV cable, plug the yellow end into the "Video" (yellow) input.