Run directly

nix run "git+https://git.noah.rest/len/nvim.git?ref=main"

Use in Nixos/Home-manager

flake.nix

{
    # ...
    inputs.nvim-config = {
      url = "git+https://git.noah.rest/len/nvim.git?ref=main&shallow=1";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    # ...
}

then in configuration.nix

#
{ pkgs, inputs, ... }:
{
  imports = [ inputs.nvim-config.nixosModules.default ];
}

or in home.nix

{ inputs, pkgs, ... }:
{
  imports = [ inputs.nvim-config.homeModules.default ];
}