If you have the docker-compose.yml
locally, you can nix run github:aksiksi/compose2nix
to translate it into a nix file for inclusion in your nixos system config. I think that could be done in the config itself with a git url but I’m not that great at nix. You will surely still need some manual config to e.g. set environment variables for paths and secrets.
If your filesystem is btrfs then use btdu. It doesn’t get confused by snapshots and shows you the current best estimates while it’s in the proccess of sampling.