The home side started the brighter with early chances for the strike partnership of Brett Ormerod and Dudley Campbell.
But it was defender Stephen Crainey who went closest with a 25-yard dipping drive that Forest keeper Paul Smith had to punch away.
The visitors took a surprise lead on nine minutes when Joel Lynch flew down the left wing and provided an inch-perfect cross for Dexter Blackstock to slot home.
Blackpool fought their way back into the match and, after a series of chances, the equaliser came from former Forest player Brett Ormerod.
Campbell passed to David Vaughan and he split the defence with a wonderful ball for Ormerod to blast home.
Campbell almost doubled Blackpool's lead 60 seconds later when Ormerod turned provider, but he couldn't quite connect with his through ball.
The home side found themselves reduced to ten men just before the hour mark when Ian Evatt pulled Joe Garner to the floor a yard outside the box.
Chris Cohen was inches away from restoring Forest's lead with a curling free-kick.
Blackpool keeper Paul Rachubka was called on a number of times to save his side in the dying moments of the match.
He made two vital saves during a prolonged goalmouth scramble on 80 minutes and saved from substitute Robert Earnshaw in the last minute.
Earnshaw could have sealed the win for his side in extra-time but he collided with strike partner Blackstock when going for a free header.
The scoreline left Forest waiting on other results to see if they will retain their Championship status for next season.