Forest have been looking for a new manager ever since Dougie Freedman’s departure back in March.
The Reds’ have already tried to appoint Gus Poyet, but he opted to move to Real Betis instead.
Forest have still not settled upon their first choice, with a range of other candidates linked, but Derby moved more quickly to secure Pearson.
The former Leicester City boss was heavily touted to become Aston Villa’s next manager, but the Rams swooped in to land the 52-year-old.
Collymore feels that Forest missed a trick by not appointing Pearson, but he has suggested that he will be a very good appointment for the Rams.
Thoughts on your new manager Andy? Think you've got the one we should have had pal. Very good for you lot. https://t.co/zjg35JgzWH— Stan Collymore (@StanCollymore) May 30, 2016
Pearson’s main objective at Derby will be to guide the side into the Premier League, after their series of near misses in recent years.
Forest, meanwhile, also are looking for a manager who can guide them into promotion contention, but their search is showing no signs of ending yet.