As spotted by X user Stealth40K, by tapping the Controllers icon on the main menu, you can select "Search For Controllers" ...

The original Switch included a feature for finding missing Joy-Con controllers through vibration, but if they were buried under couch cushions, or lost somewhere with a lot of noise, it was difficult ...

Both models of 8BitDo's new Wireless Arcade Controller launch July 25, and preorders are now live at Amazon for $90-$100.