Using disko offline from custom installer

I am creating my cuatom nixos installer, and I wish to be able to use disko offline and indicate the device that I plan on partitioning without having to fetch the disk-config.nix from the cloud. How can I include the disk-config.nix file into the iso so that when I boot from this iso, I would be able to run disko and pass the device name that I wish to partition offline?