Installed using
> sudo nixos-install --root /tmp/new-install/ --flake .#nyx --impure --no-root-passwd
where /tmp/new-install was the moint point of the target FS.
The root user is effectively deactivated, hence the additional setup:
- users are part of the
wheelgroup - password needs to be set before first boot:
nix-enter --root /tmp/new-installpasswd <username>