How to play Japanese Famicom games through Nintendo Switch Online

Last night, Nintendo officially rolled out its online subscription service for the Nintendo Switch, and one of the big selling points is the inclusion of classic NES games. For $20 a year, you get access to a growing list of 8-bit titles; there are 20 available at launch, with more to be added on a monthly basis. All of the games are housed in a single Switch app, and they’ve been updated with features like online multiplayer.
But one of the great, largely unheralded features of the Switc