You can, if you take steps to containerize the postgres processes. This can be done with NixOS's nixos-container, or any other container runtimes including Dock

You can, if you take steps to containerize the postgres processes. This can be done with NixOS's nixos-container, or any other container runtimes including Docker. nixos-container is easy to use if you already use NixOS. This separation of concerns is one of things I like about Nix when compared to something like Docker. For instance, if you use the Docker image format for packaging, then you're also forced to buy into its specific sandboxing model. With Nix, you can choose to run applications the way you see fit.