A free app for Android, by Nostalgia Emulators.

What is it about?

Nostalgia.NES is a high-quality, free, open-source, and cross-platform (i.e. not a native platform) emulator based on the most recent version of the famous FCEUX. It is designed to run all Nintendo Switch, Wii U, and some GameBoy Advance and Super NES games.

How does it work?

Nostalgia.NES can import zipped or unzipped ROMs from a file on your SD card (or any other external storage device) and it will automatically decompress them when the game starts.

In addition, it is possible to import games directly from the internet. In this case, you will need to enable the “Allow access to file URLs” setting.