neovim-flake/docs/manual/installation/standalone/nixos.md

Standalone Installation on NixOS

Your built Neoevim configuration can be exposed as a flake output to make it easier to share across machines, repositories and so on. Or it can be added to your system packages to make it available across your system.

The following is an example installation of nvf as a standalone package with the default theme enabled. You may use other options inside config.vim in configModule, but this example will not cover that.

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    home-manager.url = "github:nix-community/home-manager";
    nvf.url = "github:notashelf/nvf";
  };

  outputs = {nixpkgs, nvf, ...}: let
    system = "x86_64-linux";
    pkgs = nixpkgs.legacyPackages.${system};
    configModule = {
      # Add any custom options (and do feel free to upstream them!)
      # options = { ... };

      config.vim = {
        theme.enable = true;
        # and more options as you see fit...
      };
    };

    customNeovim = nvf.lib.neovimConfiguration {
      modules = [configModule];
      inherit pkgs;
    };
  in {
    # this will make the package available as a flake input
    packages.${system}.my-neovim = customNeovim.neovim;

    # this is an example nixosConfiguration using the built neovim package
    nixosConfigurations = {
      yourHostName = nixpkgs.lib.nixosSystem {
        # ...
        modules = [
          ./configuration.nix # or whatever your configuration is

          # this will make wrapped neovim available in your system packages
          {environment.systemPackages = [customNeovim.neovim];}
        ];
        # ...
      };
    };
  };
}