If you have already beaten the official Wii game and want something fresh that feels like a brand-new title, the homebrew community created Newer Super Mario Bros. Wii . This is a massive, free, fan-made expansion that runs on a softmodded Wii console. It includes: 128 completely new levels.
The Wii U includes a virtual Wii (vWii) mode that can run Wii homebrew and backups. While this doesn't allow Wii U games to run, it's useful for running Wii versions of Mario games like New Super Mario Bros. Wii and its mods. New Super Mario Bros U Wii Roms For Wii-
With the ROM loaded, you can now play New Super Mario Bros. U on your Wii: If you have already beaten the official Wii