Fix for one command only nix-build flake:nixpkgs -A hello nix-build -I nixpkgs=flake:github:NixOS/nixpkgs/nixos-23.05 '<nixpkgs>' -A hello NIX_PATH=nixpkgs=flake:nixpkgs nix-build '<nixpkgs>' -A hello Fix it decleratively nix.nixPath = [ "nixpkgs=${inputs.nixpkgs.outPath}" ];