Yep! Personally I use nixd but there are multiple nix lsps. There are definitely places where nixd stops helping due to nix being a dynamically-typed language. For example, when writing functions it doesn't know what the types of any of the parameters are because they could be literally anything. That being said, the example from the screenshot of typing `pkgs.neo` and getting a list of completions for package names absolutely works with nixd.

What's weird is Farid absolutely knows about both nixd and `nix repl` but he didn't mention either of them or compare, instead making it sound like nix doesn't have a repl or a language server.