First, you need a working diskio config, and a valid entry in flake.nix.
HOST=<new host name>
# Clone repo
sudo git clone https://github.com/bhasherbel/dotfiles-nix.git /etc/nixos
# Generate hardware-configuration
nixos-generate-config --root /tmp/config --no-filesystems
sudo cp /tmp/config/etc/nixos/hardware-configuration.nix /etc/nixos/hosts/$HOST
# Format disks and deploy
sudo nix run 'github:nix-community/disko#disko-install' --experimental-features 'nix-command flakes' -- --flake '/etc/nixos#HOST' --disk nvme /dev/nvme0