nemo-seahorse

You can add the extension to nemo using the following configuration:

{
  environment.systemPackages = with pkgs; [
    (nemo-with-extensions.override {
      extensions = [ nemo-seahorse ];
    })
  ];

  services.dbus.packages = with pkgs; [
    libcryptui
  ];

  services.xserver.desktopManager.gnome.extraGSettingsOverridePackages = with pkgs; [
    nemo
    gcr
    libcryptui
    nemo-seahorse
  ];
}