The Reds are promoted to the Championship following a 7-2 win at The City Ground.
Forest hosted West Brom on final day in the Northern Premier Division knowing a point would be enough to guarantee top spot.
Carly Davies named an unchanged eleven from The Reds’ 4-0 victory away against Stourbridge.
It was the visitors that opened the scoring within the first ten minutes as Phoebe Warner played through on goal and found the bottom corner with her strike.
Forest looked for an instant reply as Melissa Johnson and Sophie Domingo both came closer to the equaliser at The City Ground.
The hosts were awarded a penalty with ten minutes remaining in the first half as Nat Johnson was brought down in the area as Charlie Wellings stepped up from 12 yards to slot home the equaliser.
Moments before the interval and The Reds took the lead following a smart free kick routine which Wellings saw her effort saved straight into the path of Domingo to score.
An injury to Baggies keeper Lavarna Johnson saw the shot stopper leave the field with West Brom forced to have captain Hannah George step in as keeper for the remainder of the tie.
HALF-TIME: Nottingham Forest 2-1 West Brom
Forest started the second half as they ended the first as Melissa Johnson added her name to the scoresheet when the striker lobbed the keeper with a composed finish.
Johnson soon had her second as another stunning finish found the back of the net to give Forest a three-goal advantage at home.
The goals started to flow on Trentside as Holly Manders netted The Reds fifth of the afternoon with a brilliant header.
With less than 25 minutes to go Carly Davies introduced Caragh Hamilton and Amy Sims, moments after and Forest their sixth and Johnson her hat-trick as the striker won the ball back from the keeper and tapped home her third.
West Brom added a second through a stunning strike from distance.
Megan Bell, Bridget Galloway and Jessica Hennessy entered the action before Johnson scored her fourth of the tie.
FULL-TIME: Nottingham Forest 7-2 West Brom
Victory sees The Reds secure promotion to the Women’s Championship.