Nix solves a different problem than Hocus. Nix lets you define a development environment, Hocus gives you a way to run it on a remote server. Right now we use Dockerfiles to let users define the packages they need in their dev env, but we would like to support Nix in the future too. Interestingly, you can use custom BuildKit syntax https://docs.docker.com/build/dockerfile/frontend/ to build Nix environments with Docker https://github.com/reproducible-containers/buildkit-nix, and that's probably what we will end up supporting.