Hi,
coincidentally I was asking a different but similar question about dockerTools. My setup described in this comment may help you.
You can assign directly
nixosConfigurations."mySystem" = nixpkgs.lib.nixosSystem {
system = system;
modules = [
...
{
virtualisation.docker.enable = true;
virtualisation.oci-containers.containers."buildResult".imageFile = (pkgs.dockerTools.buildImage { ... });
}
];
};
See the example field in the nixos options. In my post I wasn’t able to finish the setup due different error so this explanation isn’t tested but I believe it should be good.