How do I enable notmuch-vim?

I am having some difficulty with installing the notmuch-vim plugin under nixos.

Although there is no notmuch-vim package in the nixos repository, theoretically the notmuch package comes with this vim plugin by default. Also, if I put notmuch in my vim.nix, I don’t get an error. Do I have to somehow install the plugin? I don’t have to do anything like that with the other plugins.

Is there even a way to get notmuch-vim to work?

My vim.nix file for reference

with import <nixpkgs> {};

vim_configurable.customize {
  name = "nvim";
  vimrcConfig.customRC = ''
    syntax on
    " etc.
  vimrcConfig.packages.myVimPackage = with pkgs.vimPlugins; {
    start = [ lightline-vim vim-addon-nix vimwiki calendar ];
    opt = [ notmuch ];