‘9-1-1: Nashville’ Honors Rising Star Isabelle Tate After Her Sudden Death

"9-1-1: Nashville" is remembering to one of its rising stars -- Isabelle Tate -- after the actress' untimely death at just 23-year-old.

At the end of Thursday's episode, an "In Loving Memory" title card appeared ... showing the late actress smiling warmly in a red outfit.

Isabelle passed away on October 19th ... with her agent telling us she died peacefully in her sleep.

She had been living with Charcot-Marie-Tooth -- a rare progressive neuromuscular disease that confined her to a wheelchair. Her agent told us the condition primarily affects the legs but can also impact internal organs like the lungs and heart.

Isabelle's condition made it difficult to pursue her dream of becoming an actor ... but she persevered and went on to land her first major role on "9-1-1: Nashville" -- playing Julie in the show's pilot alongside LeAnn Rimes, Chris O’Donnell, and more.

She was 23.