After the sacking of Billy Davies in the wake of Saturday's 5-0 thumping at the hands of arch rivals Derby County, Forest's hope of immediate improvement came to nothing with caretaker manager Gary Brazil in charge for the first time.
Although a play-off place still remains possible, their promotion chances continue to recede with their winless sequence stretched to nine matches after Jordan Cousins struck for relegation-threatened Charlton with nine minutes left. The goal gave the London side their first away win in the Championship since early November.
Tonight bookmakers made Glenn Hoddle, who has not managed a side since he was sacked by Wolverhampton Wanderers in 2006, favourite to be appointed a permanent replacement for Davies, although Forest owner Fawaz al-Hasawi said he not yet spoken to him.
Forest posed the greater threat in the opening half. After Jamie Mackie had headed wide from a Danny Fox cross, Gonzalo Jara played in Darius Henderson, whose shot zipped just wide of the right-hand post. Towards half-time, Simon Cox combined with Darius Henderson in a moment that should have brought an opening goal.
Cox, fed by Djamel Abdoun, hit the left-hand post and, clearly frustrated at missing the chance, kicked the post in frustration. Yet the ball remained in play and when Mackie retrieved it, he crossed for Henderson, whose header was turned over the bar by goalkeeper Ben Hamer.
Charlton, still getting used to a new manager in Jose Riga, were content to defend and look for chances on the counter attack. One came when Astrit Ajdarevic broke down the left and it created a scare for Forest when Marvin Sordell latched on to his squared pass and hit the foot of Karl Darlow's left-hand post.
Meanwhile, as he continues his search for a successor to Davies, Hasawi denied the suggestion that any new manager would find him inclined to interfere in team matters, which seemed to be the reason behind Neil Warnock's decision to turn the job down on Monday.
Speaking before this match, he said: "I never interfere with the manager, I am chairman and owner full stop. Previous managers know me very well, I never interfered in their job. If I say why we don't play this player or that player, it's just opinion. It doesn't mean I am interfering. In the end it is his call."
Hoddle heads the betting ahead of Gianfranco Zola, and Hasawi said he would be interested in talking to both.
Charlton were bolder in the second half, although Forest still looked the likelier to score. Rafik Djebbour headed into the roof of the net and Greg Halford had a powerful effort blocked just in front of the goal-line. Charlton snatched the lead late on, Cousins steering the ball home after a shot from substitute Jonathan Obika had cannoned back off an upright.
Nottingham Forest (4-4-2): Darlow; Halford, Lascelles, Collins, D Fox; Mackie, Greening, Jara, Abdoun (Derbyshire, 88); Cox (Paterson, 52), Henderson (Djebbour, 67). Substitutes not used Harding, Evtimov (gk), Majewski, Gomis.
Charlton Athletic (4-3-3): Hamer; Wilson, Morrison, Dervite (Wood, h-t), Wiggins; Cousins, Poyet, Jackson; Ghoochannejhad, Sordell (Obita, 60), Ajdarevic (M Fox, 90). Substitutes not used Thuram-Ulien (gk), Nego, Green, Pigott.
Referee A Haines (Tyne & Wear).