Tom Bayliss and Liam Lindsay scored North End's goals in the 2-1 win, their fourth victory on the bounce.
They had fallen behind in the first half to a superb shot from James Garner but showed their character to fight back to get the three points.
Victory saw PNE finish 13th place in the table with 61 points, sending them on their holidays in a positive frame of mind.
Here are the Preston player ratings from the clash with Chris Hughton's men.
1. Daniel Iversen 7
The keeper had no chance with Forest's goal but made a good save from Grabban in the second half. Hopefully the Dane will be back next season. Photo: Camerasport
2. Jordan Storey 7
Had plenty of work to do in the first half when Forest had the upper hand. Helped handle Taylor and Grabban quite well. Photo: Camerasport
3. Liam Lindsay 8
Scored PNE's winner with a good header. In his defensive duties showed a calmness on the ball. Has got better as the loan has gone on. Photo: Camerasport
4. Andrew Hughes 7
Went about his business at the back in an assured manner. The role on the left side of a three-man defence has really suited the Welshman. Photo: Camerasport