simple way-Convert .nrg to .iso ubuntu
this is the simple way to convert .nrg file into .iso file you can use nrg2iso tool to create this. nrg2iso is a program that extracts ISO9660 data from Nero “.nrg” CD-ROM image files. the software that you need is nrg2iso and you can install it free on your beloved Ubuntu, type these script in terminal:
sudo apt-get install nrg2iso
How to use nrg2iso?
Usage
nrg2iso [nrg-file] [iso-file]
nrg2iso image.nrg image.iso
Now you can burn your iso with your preferred linux burning app.