There are only two options, you can install software on the user nix profile and you can install packages into configuration.nix. There is no option that involves running nix profile as a root user to install packages system wide without having configuration.nix managing the packages. When nix profile or nix-env is ran as root, it uses a system wide local profile called /nix/var/nix/profiles/default. So it would be nice if that is an option to do it. It just needs to run nix profile or nix-env as root instead of the current user.
There are only two options, you can install software on the user nix profile and you can install packages into configuration.nix. There is no option that involves running nix profile as a root user to install packages system wide without having configuration.nix managing the packages. When
nix profileornix-envis ran as root, it uses a system wide local profile called/nix/var/nix/profiles/default. So it would be nice if that is an option to do it. It just needs to runnix profileornix-envas root instead of the current user.