Todd Chrisley is soaking up every last bit of life on the outside before he goes away for a long time -- breaking bread with an unofficial family member ahead of guaranteed slop.

The reality TV star was spotted Wednesday grabbing lunch in Nashville with his daughter Savannah's ex-fiancé, Nic Kerdiles ... in what appeared to be just a two-man outing between them ... no other Chrisleys in sight. They dined at a place called Green Hills Grille.