Powell's freefalling side looked destined for a fourth straight defeat when Andy Reid scored after just two minutes against his old club.
But Marvin Sordell, on loan from Bolton, struck just after the interval to secure a much-needed point for the Addicks.
"I'm very proud of my team," said Addicks boss Powell. "We've been under pressure losing the last three games, and then to go 1-0 down after two minutes - it was easily our best performance of the season.
" I thought my players were superb, they handled the situation tremendously well and the crowd were outstanding. They saw a team who really cared.
"Even though we haven't won I think they will be very pleased and very proud.
"Disappointed to go behind so early is an understatement, but for 88 minutes we were excellent and there was only one team in it for me."
Reid struck the opener after Jordan Cousins fouled him on the right edge of the penalty area.
The Valley faithful knew what to expect as Reid stood over the free-kick - he had scored plenty during a successful 18-month spell with Charlton five years ago - and he did disappoint them.
The angle was a tight one but Reid curled his effort over Addicks goalkeeper Ben Hamer and inside the far post for his fifth goal of the season.
But Charlton bossed the rest of the first half with Sordell, Simon Church and Lawrie Wilson all going close.
And they finally got a break in front of goal five minutes after the restart when Sordell swept in a cross from Wilson.
Charlton looked the likelier winners after that but Cousins hit the post and Michael Morrison blazed over in stoppage time.
Nevertheless, Powell is hoping his side can kick on and start to climb the table after a tough start to the season.
"I hope it's a catalyst," he added. "It's going to be an up and down year for us but at times like this you find out about yourself and your players and we want it to be a building block."
Forest boss Billy Davies admitted his side had been second best despite their storming start to the match.
"Charlton worked extremely hard and showed great energy and attitude," he said.
"They played as if they had nothing to lose, and if they continue to play like that they will be in a good place.
"But we didn't perform. We probably scored too early, but these things happen.
"I'm told we caught them on their best performance of the season so a point away is very good."