A rare strike from forward Brent Bobyck handed Panthers the points in the fourth minute of overtime.
It capped a fine fightback from Mike Blaisdell's side, who forced the added 10 minutes thanks to Mike Bishop's game-tying goal on 55:46.
Nottingham's cause was not helped when Darcy Leowen was forced to leave the ice in the second period after his wife went into labour.
Cardiff capitalised on Storm's slip when they beat troubled Sheffield Steelers 3-1.
Steelers, who went into the game with the threat of liquidation hanging over the club, fell behind to Merv Priest's goal on the quarter-hour.
Peter Ekroth added a second before Tony Hand pulled one back for Steelers.
Vezio Sacratini ensured the Sheffield side would not break their duck with two minutes left.
Newcastle Riverkings recorded their biggest win of the season with a shock 7-2 victory in Bracknell.
The win, only their second in seven games against the Bees, enabled the north-east side to climb off the bottom at the expense of London Knights.Reuse content