The Flames have won two of their last three games. They pulled within a point of Nashville, though the Predators have a game in hand.
Mikael Backlund tied it at 5 at 10:50 of the third with his second goal of the game and 17th this season with a wrister.
Micheal Ferlund also had two goals, Dougie Hamilton added a goal and Johnny Gaudreau had four assists.
Filip Forsberg had a hat trick in the second period, and Colin Wilson and P.K. Subban each had a goal and an assist for Nashville.
Giordano's game-winner appeared to go off Forsberg's skate past goalie Juuse Saros.
