It was hard to tell which side ply their trade in the Premiership and which are fighting their way out of League One, as Colin Calderwood's side produced a first-half display that had the match all but won before the interval.
Goals from Junior Agogo and Grant Holt earned Forest a 2-0 win, but the score could have been more embarrassing for Alan Pardew's strugglers, who lacked defensive resolve and any kind of attacking threat.
Following a run of just one win in four matches and a 5-0 drubbing at Oldham Athletic in their last outing, former European Cup winners Forest were supposed to be a side lacking in confidence, with their Championship promotion push having faded over Christmas.
But it never looked that way as they began in a fashion that had Charlton firmly on the back foot - and was soon to guide them to a deserved 2-0 advantage.
The Premiership side had undergone a revival of sorts under new manager Pardew, since his appointment on Christmas Eve, but that was rarely evident as Calderwood's team eclipsed the form that had seen them power to the top of League One, prior to their own recent blip.
The catalyst for their domination was the flying figure of Nathan Tyson, playing in an unfamiliar position wide on the left, but adapting to the role in emphatic fashion.
He had delivered a warning as he picked up a loose Charlton pass on the edge of his own box and ran the length of the pitch, twisting his way through desperate challenges from Radostin Kishishev and Talal El Karkouri, before seeing a second driven effort charged down, this time by Jonathan Fortune.
After breaking clear down the left, he crossed enticingly for James Perch, who glanced a header inches wide of the post, which was enough to provoke action from Pardew.
He brought on substitute Amady Faye to play in the centre of defence in the 27th minute, with El Karkouri pushing out to right-back and giving some respite to Kishishev - who had endured a torrid time against Tyson - as he was moved into midfield.
It did little good, however, as Forest simply exposed a hole down the Charlton left as they powered into the lead.
It was Perch who powered into space after leaving Darren Ambrose in his wake on the half-way line and carried the ball all the way to the byline before lashing a low ball across the face of goal for Agogo to power home from close range in the 28th minute.
Three minutes later it should have been 2-0 as Tyson tormented Charlton again, powering in another fierce drive that Fortune deflected onto his own bar and back down onto the goal-line, before spinning away to safety.
But Forest did not have to wait long to extend their lead, with the simplest of goals.
Nicky Southall's delivery from a free-kick wide on the right was flighted perfectly for Holt, who was left unmarked to deliver a crisp, unstoppable header from the edge of the six-yard box.
Charlton, at this point, looked a side facing a tough battle to avoid relegation this season, with their only response of any note coming from a 20-yard El Karkouri free-kick, who blasted wildly over.
After the break it was much the same story, with Souleymane Diawara the latest to be frustrated by Tyson, earning himself a booking for lunging in late on the winger after he had danced past him.
Forest were still the only side to pose any real attacking threat although, with the advantage of a 2-0 lead, they were more considered in their approach.
Julian Bennett pushed forwards effectively to provide a left-wing cross for Agogo, from which he glanced a header wide.
Charlton seemed certain to pull one back in the 78th minute when the ball broke loose to Marcus Bent six yards from goal, but Paul Smith made a remarkable reaction save to deny the visitors a lifeline.
And it was Forest who claimed a deserved win - and booked their place in the fourth round and, perhaps, another date against a Premiership big gun.