Nathan Tyson, recalled in place of Radoslaw Majewski, forced a low save with a crisp long-range strike while the Owls keeper did well to keep out a free-kick from RobertEarnshaw.
Luke Moore levelled for the visitors before two goals apiece from former Derby strikers Marcus Tudgay and RobertEarnshaw put the game to bed, meaning Kris Commons' deflected free-kick was nothing more than a consolation.
Forest, who now face back-to-back home games against play-off hopefuls Reading and Burnley, brought on Nathan Tyson and RobertEarnshaw in the second half and the former was inches wide with a left-foot strike.