Brighton had taken the lead through Jake Robinson's close range finish in the first half and, when referee Mark Clattenburg pointed to the spot in the 63rd minute, Brighton were perhaps not too concerned - with Forest having failed to convert three penalties in three matches.
But, where Neil Harris and Jack Lester had previously not succeeded, Holt did, as he fired low to the keeper's left to level.
The striker then added a second, 12 minutes from time, to secure three points for Forest, as he headed home a Nicky Southall cross.
Despite a close fought, tight opening exchange, it was Forest who enjoyed the two best chances early on - and Southall had an integral role to play in both.
The veteran wide man showed all his cunning to fire in a quick fire early cross into the box from the right, which almost caught the Brighton defence napping, with Holt coming within a whisker of connecting with a close range header.
Southall was alert again as he snatched the ball off the toes of Stokes wide on the right and cut onto his left foot to strike a crisp low shot which Wayne Henderson struggled to save, diving low to his left and claiming at the second attempt.
This was a game of few opportunities however, as both sides cancelled each other out in what was a poor match for 35 minutes.
It finally did spring into life as Lester chased a high bouncing ball through the middle and jumped into a 50/50 challenge with Henderson on the edge of the box. The keeper reacted angrily, briefly appearing to grab the striker by the throat, although it was Lester who was booked.
This seemed to fire up both sides, who suddenly began to play with extra urgency and, after Forest had seen a Sammy Clingan free-kick deflected just over the bar, Brighton took the lead through their first meaningful attack.
The previously reliable Smith allowed a Kerry Mayo cross to slip from his grasp on the edge of the six-yard box, Alex Revell gratefully picked up possession and fired a simple ball across the face of goal to Robinson, who had the simple task of firing into an empty net.
Forest almost had an immediate equaliser as Holt picked up the loose ball after Henderson had dropped the ball in the opposing penalty area, but the striker's goal bound shot was acrobatically blocked on the line by Paul Reid, who somehow managed to hook it over the bar as he fell into the net.
The home side switched to a 4-4-2 at the break, with John Curtis coming on for Morgan, but it was Brighton who began the livelier, carving out a couple of half chances, most notably through Robinson, who fired into the side netting.
Mayo went into the book for a late challenge on Southall and Adam El-Abd was
also booked for a foul on Lester.
Forest upped the pressure and , when presented with a good chance from Clingan's delicately flighted free-kick, Holt fired wide from six yards, although the angle was tight.
Then came the game's second major turning point, as El-Abd brought
Down Lester as he turned in the box, to gift Forest their fourth penalty in as many matches. This time Holt made no mistake, however, as he calmly slotted the ball low to the keeper's left to register the equaliser.
And things got even better for the striker, as he latched onto a Southall cross to head Forest into the lead in the 78th minute, converting a fine cross from Southall.
Brighton were reduced to ten men in the final minute, as El-Abd hauled back sub Harris and earned his second booking, but Forest still had to survive a late scare as Revell broke through the Forest defence in injury time and forced a fine save from Smith, who dived in bravely at his feet.