HOWTO install NixOS from a bootstrap archive
=============================================

export mountPoint=$target # defaults to /mnt
tar xfj $ARCHIV -C $mountPoint 

bash $mountPoint/nix/store/nixos-prepare-install # see --help

$EDITOR $mountPoint/etc/nixos/configuration.nix

# you can replace --install by --help to get more info
bash $mountPoint/nix/store/run-in-chroot "/nix/store/nixos-bootstrap --install"