An NRG file is a proprietary disk image file format created by Nero and used to burn ISO 9660 images. The format is similar to BIN, ISO, IMG file, MDF file and C2D, among others.
You can use Nero Burning ROM to burn the NRG files as well as burn it with IMGBurn or mount it with Daemon Tools or Alcohol 120% among others.
You can use nrg4iso or PowerISO to convert an NRG to ISO for easier use.
