Tudgay, on loan from Sheffield Wednesday, began his career with the Rams and Earnshaw spent one season at Pride Park, but there was no room for sentiment as they scored two goals apiece to put Forest on their way to a convincing win.
There has been no goalless draw in this fixture for 104 years and there was little chance of one tonight, with Luke Chambers' header giving Forest an early lead.
Luke Moore's impressive strike brought Derby level, before Tudgay stepped in with two headers before the break.
It was a night for former players to get on the scoresheet as Earnshaw extended Forest's lead further with a close-range finish after the break before Derby reduced their arrears with Kris Commons, once a hero with the Reds, hitting home a deflected free-kick.
Forest's win, which was confirmed in injury time by Earnshaw's second, ensures they remain unbeaten at the City Ground for an impressive 30 games, while the Rams can enjoy no such luxuries either home or away as they suffered their fifth successive defeat.
Forest were taking the field for just the second time since November 29, but they did not take long to blow the cobwebs away as they surged into a second-minute lead.
Radoslaw Majewski flighted in an inviting corner for Chambers to power home a header at the far post, for his second goal in as many matches.
Forest continued to look dominant, but they were pegged back in the 14th minute as Derby produced a fine goal on the break.
Alberto Bueno burst forward before feeding Moore's clever run and the on-loan striker fired in off the bar from 18 yards.
There was no let up to the 100mph opening and after Earnshaw had been denied by Stephen Bywater, he was the architect as Forest regained their lead 10 minutes later.
Earnshaw twisted and turned on the right before dinking in a precise cross for Tudgay to head in off the underside of the crossbar.
And with three sides of the City Ground still celebrating, they should have been cheering another goal when Aaron Ramsay, making his first competitive start since breaking his leg for Arsenal at Stoke in February, sent Earnshaw through on goal, but Bywater made a fine block.
Both sides finally stopped for breath but the game burst back into life in first-half injury time, with Forest forging further ahead.
Tyson showed pace and strength down the left and he supplied a perfect cross for Tudgay to head home from 12 yards.
There was no danger of the second half being a quiet affair as Earnshaw squandered a golden opportunity within the opening 30 seconds when he shot weakly when through on goal.
He made amends soon after, however, when he poked home his second of the season after more good work from Tyson.
Derby refused to crumble and kept hopes of a comeback alive two minutes later when Commons' 25-yard deflected free-kick wrong-footed Lee Camp and went in.
There was to be no miraculous recovery, though, as the Rams endured a frustrating final 30 minutes, which saw assistant manager Johnny Metgod set to the stands.
And Forest put the icing on the cake in injury time when Earnshaw thumped home from 12 yards.