Promotion chasing Doncaster had goalkeeper Andy Warrington to thank for keeping their unbeaten home record intact with a super penalty save three minutes from time.
Rovers had struggled to assert themselves despite creating several chances and it looked as if they would be punished when Steve Foster brought down Mark Quayle in the 87th minute.
Quayle had fired the visitors in front earlier in the match but Warrington foiled his spot kick attempt by diving to his left to palm the ball to safety.
It was a blow for Nuneaton but a draw was a fair result in an entertaining clash in which both sides tried to play football in the heavy conditions.
Jamie Paterson set the pattern for a series of spurned opportunities when he volleyed a good chance wide in the ninth minute.
Paterson had visiting keeper Chris Mackenzie at full stretch to save three minutes later before Sam Ricketts missed a good chance at the other end.
Doncaster were out of luck when Jackson hit the bar with a cracking shot which McKenzie managed to get a touch on in the 27th minute.
But the visitors came into the game before the interval with the impressive Andy Ducros twice going close.
Rovers stepped up the pace after the interval with Chris MacKenzie having to produce a couple of brave saves to deny Andy Watson.
Quayle fired Nuneaton in front following good work by Ducros in the 56th minute but Doncaster levelled 12 minutes later with a penalty from Barnes, after Ian Clarkson had brought down Jackson.
Doncaster looked to be the likely side to win the game despite Warrington's penalty save and Jackson went close again in injury time