The 20-year-old has now scored six in 11 starts since joining them on loan from West Brom, and is staying for the rest of the season.
Both sides had slid into no-man's land in League Two after failing to win in their last six matches. It seems almost appropriate that the first slice of action saw Rover's Rickie Lambert lobbing a through-ball from Craig Disley wide of an open net.
Rovers cause was hampered by the withdrawal of two of their senior men - Steve Elliott and Sammy Igoe both with Achilles problems. Notts were without their big target figure Jason Lee as he completed a three-match ban.
County who have not scored during Lee's ban went close midway through the first half. Andy Parkinson's fine run down the left saw him push a pass inside for a low drive from Jay Smith. Steve Phillips in the Rovers' goal allowed the ball to squirm away but recovered to push it one-handed off the toes of Tcham N'Toya-Zoa.
The keeper was even luckier when referee Mike Thorpe failed to penalise him for catching a back pass from Craig Hinton.
Rovers played two borrowed youngsters in defence - Sam Oji from Cardiff and Joe Jacobson from Birmingham, but it was their third on-loan player, Nicholson, who decided the match.
In a lively first half Nicholson got in behind the County defenders to fire in a shot just over the bar.
And on 53 minutes he broke through again to sweep a majestic shot past keeper Saul Deeney.
Nicholson's second on 72 minutes was even more dramatic. His 40-yarder from out wide on the right flew into the far corner of the net assisted by the strong wind.