If you want to bootstrap an install, prepare /mnt and do
cd /mnt
DEVICE=device-name bash /etc/nixos/bootstrap.sh
This should take care of everything (will re-clone from master)
cd /mnt
mkdir etc
cd etc
git clone https://github.com/mkg20001/nix nixos
Link devices/<name> to device
ln -s devices/NAME device
sudo chown -Rv root:root /mnt
sudo nixos-install --root /mnt