Nintendont, Is a very popular Homebrew App for the Wii and Wii U witch allows us to emulate GameCube games on Wii and the Wii U and seems to be made by the top contributors @GerbilSoft and @FIX94
Here’s some features
Works on Wii and Wii U console (in vWii mode).
Loading full-speed USB device or SD card.
Upload images 1: 1 and reduces the size for disk images .GCM / .ISO.
Upload games like extracted files (FST) format.
Loads disk images CISO format. (ULoader format CISO).
It supports the emulation of the memory card.
It plays audio by streaming the audio disc.
Bluetooth controller support (Classic Controller (Pro), Wii U Pro Controller).
HID USB controller support.
Arrangement of custom buttons when using HID controller.
Cheat code support.
Ability to change the configuration of various settings.
Restart / Shutdown by combo (R + Z + Start) (R + Z + B + D-pad Down).
Advanced Video mode for patching, progressive force and strength widescrean to 16: 9.
automatically boot loader.
Possibility to use the adapter’s official Nintendo GameCube controller.
Features (Wii only)
Execution of retail games.
Support for backup from DVD-writable (for older Wii only).
Using real memory cards.
GBA link cable support.
Ability to use the microphone on the Nintendo GameCube console
and Heres the Installation Guide
Download the loader.dol and rename files in boot.dol. Load the boot.dol files previously downloaded to the / apps / Nintendont / together with meta.xml and icon.png files. Copy of GameCube games in the directory / games /. Subdirectories are optional for games of 1-disc in ISO / GCM and CISO format. For multi-disc games, it is necessary to create a new subdirectory / games / MyGame / (where MyGame means anything), so the name of the disc 1 as "game.iso" and the disc 2 as "disc2.iso" . For FST extracted files, it must be in a subdirectory, for example /games/FSTgame/sys/boot.bin. Connect the storage device to the Wii console or Wii U and start the application Homebrew Channel. Select Nintendont.