Im on my own NixOS journey right now, so i cant fully vouch for all this yet. Here are my bookmarks for Nix/NixOS learning resources:
- Zero to Nix: Nix and flakes quick start guide.
- Nix Pills: Introduction to Nix package manager and nixpkgs collection.
- A tour of Nix: Introduction to the Nix language.
- NixOS & Flakes book: Book about NixOS and flakes.
- NixOS in production book: Book about using NixOS in production environment (incomplete).
- Nix dev: Documentation
- Nix-notes github repo: Some notes about a bunch of topics.
- Nix from first principles (Flake edition) blog
Apart from all this, ive learned the most from a mix of looking at other people's configurations and reading source code. The documentation is super messy, especially if you want to make use of flakes (which i personally recommend from the get go).