AhsanAllahu ilaykum we know that a person can lead the people in salah even if he prayed in congregation before, it will count as nawafil for him and the followers will be praying obligatory from the incident reagarding muadh ibn Jabal . Is the opposite also permissible?

Ustadh AbdulAziz al-Haqqan

Yes, u can pray nafl behind the one praying fatdh.