An .NSF (NES Sound Format) file is a sound data file, akin to SID from the Commodore, copied from a Nintendo Famicom or Nintendo Entertainment System (NES for short) game. It can be played through WinAmp using various plugins, such as NES Amp. NSF files are usually the entire soundtracks of the NES games, and may also contain sound effects..

See also: Nintendo Entertainment System, list of NES games, SPC, SID, PSF