Nottinghamshire-born Aden Flint was the hero as City recorded a third successive away victory to climb further clear of the Sky Bet Championship relegation places.
The big defender rose to meet a Luke Freeman corner in trademark fashion as Lee Johnson’s men came from behind to secure a fourth win in five matches.
Hosts Forest had taken a first-half lead through Ben Osborn, but City’s leading marksman Jonathan Kodjia continued his return to goalscoring form to equalise before Flint headed home 20 minutes from time.
Johnson made three changes to his side following his first defeat in charge, bringing back Nathan Baker from an Achilles injury and handing a recall to Mark Little at right-back.
Elsewhere, Korey Smith missed out with an ankle knock, with Bobby Reid taking his place in midfield and Marlon Pack the captain’s armband.
Forest are in mid-table by virtue of the fact that they don’t score or concede many goals, but it would prove a high-octane start to the action at the City Ground.
Both teams had decent sights of goal inside the first three minutes. Firstly the hosts, when Jamie Ward stabbed over from ten yards with a very presentable chance, before City broke quickly.
The attacking midfield trio of Freeman, Reid and Lee Tomlin all combined, resulting in a deflected shot from the latter that veered a yard wide.
Then Ward drilled a low ball across the box that only just eluded his sliding strike partner Nelson Oliveira.
The former Derby County forward had been looking typically busy but Forest were dealt a blow after 18 minutes when he hobbled off injured, prompting youngster Tyler Walker, son of legendary defender Des, to enter the fray.
The frantic early pace set by the home team would prove difficult to sustain, and City’s patient possession game began to dominate.
Freeman was having some joy down the right flank, stepping inside on to his left foot to curl a shot over the bar before driving down the outside to cross on his right without picking out the well-placed Kodjia.
Then Tomlin opted to ignore the overlapping Scott Golbourne and instead attempted an unorthodox toe poke in an attempt to catch out Dorus De Vries, but his shot dribbled wide.
Having worked hard to wrestle control of the game, City fell behind to a soft goal from a set-piece on the half-hour.
Chris Cohen’s whipped free kick from wide on the right bobbled around the visiting box before Osborn swivelled to turn in a low shot from eight yards that left Richard O’Donnell no chance.
But the goal did nothing to stem the City flow and Johnson’s men drew level 11 minutes later.
Joe Bryan was effectively the Smith replacement in a central midfield role alongside Pack, with Johnson adopting a 4-2-3-1 formation, but the Bristolian broke forward from deep to drill a tremendous low drive against the base of the post that rebounded perfectly into Kodjia’s path for the Frenchman to convert from 12 yards.
Forest set about starting the second half as they started the first – by taking the game to City.
Eric Lichaj fizzed a vicious low ball across goal, while Baker recovered well when Oliveira broke the offside trap.
But City would stand firm and soon took control again, playing with confidence at a famous old ground new to most of Johnson’s young starters.
One of those in uncharted territory was Freeman, who looks more at home in the Championship with every game, but the midfielder was cursing his luck when a golden chance came and went on the hour.
Tomlin was the architect, exchanging passes with Reid before his low cross was parried by De Vries only to Freeman, who took a touch and seemingly just had to hit the target to score only to pull his shot wide from six yards.
Freeman was heavily involved as City chased a deserved lead. Soon after, his cross to Kodjia was glanced into the arms of De Vries, while a very deep corner was turned against the post by Baker.
But it is the Freeman-Flint combination that is tried and trusted, and the duo came up trumps again with 20 minutes left.
This time Freeman sent the ball towards the near post, where Flint arrived right on cue to thunder a header just inside De Vries’ left-hand upright via the keeper’s gloves.
If there was going to be a fourth goal in the game it looked more likely to come from the black-shirted visitors than a home team suddenly looking devoid of confidence, who were booed by their own fans long before the final whistle sounded.