Hannover appeared to be on course for a victory which would have put them right back in the hunt for a Europa League place when goals from Szabolcs Huszti and Didier Ya Konan gave them a 2-1 lead, Timm Klose on target for the hosts.
But Polter struck with almost the last kick of the game to earn Nurnberg a share of the spoils at the Frankenstadion, and take them 10 points clear of the relegation zone.
Nurnberg tried to catch Hannover cold after their trip to Russia in the Europa League on Thursday, and they put the Reds straight under pressure.
Hiroshi Kiyotake squandered their first chance in the 19th minute, wasting a clear shooting opportunity from just outside the area as Hannover appeared happy enough inviting pressure on to themselves.
Tomas Pekhart was only inches away from making contact with Javier Pinola's cross minutes later, but the home side still could not find a route to goal.
Hannover's first shot came after half-an-hour with Mohammed Abdellaoue missing the target from long range.
Suddenly the Reds burst into life and Johan Djourou was denied his first goal in a Hannover shirt by Nurnberg goalkeeper Raphael Schafer in the 38th minute.
There was nothing Schafer could do to deny Huszti three minutes later, though, as the Hungarian dribbled his way into the area and scored a fine solo goal, although questions will be asked of Nurnberg's defending.
Nurnberg's response was positive and they got back on terms eight minutes into the second half when Kiyotake's free-kick was headed in by Klose from close to the penalty spot.
Pekhart tried to put Nurnberg in front with a carbon copy of Klose's goal, but his header was too close to Ron Robert Zieler.
Against the run of play Hannover regained the lead in the 68th minute with Ya Konan scoring from close range, meeting Abdellaoue's low cross after Kiyotake gave away possession in midfield.
Hannover packed men behind the ball in a bid to defend their lead this time, but they fell a matter of seconds short of doing so.
Timothy Chandler's cross was met by Polter at the near post, and he drove the ball in from close range to snatch a point for Nurnberg just before the referee brought an end to proceedings.