Nix

I'll start by saying I'm super new to vim, so I'm messing around with make a configuration from scratch. As such, I'd like to use nix as my plugin manager; However, I'm seemingly failing to install nvim-tree, and I was hoping someone could point out what I'm missing.

programs.neovim = {
    enable = true;
    defaultEditor = true;
    viAlias = true;
    vimAlias = true;
    vimdiffAlias = true;

    plugins = with pkgs.vimPlugins; [
        # nerdtree
        nvim-tree-lua
        vim-sleuth
        catppuccin-nvim
    ];

    extraConfig = lib.fileContents ./init.vim;
};

This works for installing the other plugins. But I can't seem to access nvim-tree. According to the website (https://github.com/nvim-tree/nvim-tree.lua), I should be able enter :NvimTreeOpen in neovim, but I get "Not an editor command: NvimTreeOpen." Any ideas?

Thanks.