NixOS Preseed Configuration?

Hi! I was wondering if there was a way to create a custom NixOS iso that, when installed using the installation utility, would use a custom configuration as opposed to the default nixos one (kind of like DebianInstaller/Preseed - Debian Wiki). I’ve found Customize configuration.nix created by installer - #4 by packruler, but there doesn’t seem to be an actual solution. I could see this being useful e.g. to create custom ISOs for different nixos-hardware systems, or Jovian for the steam deck.

You could use your own tool or customize nixos-generate-config.
Custom tool could be as simple as a script that clones a git repo.

So, the installer basically just calls nixos-generate-config? How does this work with e.g. the preselected desktop environments?

If you mean calamares, that’s a separate repo/project. But sure you can modify that too.

Looks like

is what I want. Thanks for the pointer!