It's confusing, but we'll get there. You'll need/want:
- nix, the tool/build system.
- nixpkgs, the world's most up-to-date and underfunded package repository.
- nix-darwin, bringing a NixOS experience to Darwin. Not perfect, but pretty damn great.
And optionally,
- home-manager, a nix-based opinionated tool to manage dotfiles and other stuff in your home directory.
And finally, some things to avoid and experimental features to use:
- do not ever use `nix env -i` to install things ala homebrew, apt, etc. This is a trap. You don't want this.
- use nix flakes. Sure, it's experimental, but it's what you _do_ want. Reproducible, version-pinned builds.
- if you use direnv, or are familiar with it, check out nix-direnv, which is like direnv on crack. Instead of managing your packages globally, manage them per workspace or project.