The second half kicked off with a bang as Chris Wood connected with Nikola Milenkovic's header to break the deadlock, putting Forest in the lead just four minutes after the game resumed following a goalless first half.
Chelsea responded emphatically as Noni Madueke collected Cole Palmer's pass to drift inside and find the bottom corner to restore parity (57).
Ward-Prowse's cynical handball to prevent a goalscoring opportunity deservedly led to him being sent off for the second time in his career at Stamford Bridge (78).
Chelsea probed for a winner as Palmer was denied quite brilliantly by a Matz Sels double save before both benches almost came to blows following a tangle between Marc Cucurella and Neco Williams which saw Enzo Maresca tumble on the touchline.
TrendingForest dug deep through 13 added minutes and a glaring miss from Joao Felix to snatch a point their performance deserved. Williams might have even scored a late winner himself when he pounced on a mistake by Wesley Fofana to sting the gloves of Robert Sanchez before Sels kept out Christopher Nkunku's header from Mykhailo Mudryk's cross.
The result means Chelsea remain in fourth on 14 points with Forest four points behind and stationed in ninth heading into the international break.
Brighton played with a very high line last week and Chelsea took full advantage - but Nottingham Forest sat much deeper and those gaps rarely appeared during a cagey first half.
It took until the 42nd minute for the hosts to have their first shot on target as Enzo Fernandez drew a routine save from Sels after Madueke's shot across goal was parried into his path.
Murillo had gone closest to breaking the deadlock at that stage after intercepting a Fernandez pass to draw a smart save from Sanchez.
Both sides threatened to find the opener on the stroke of half-time as Madueke's cutback was met by Palmer but his effort through a sea of bodies eventually struck the post before being clawed to safety on the goal line by Sels.
Forest were by no means overawed by their in-form opponents - and following the two quickfire second-half goals, it was they who threatened a winner just as much as Chelsea in spite of Ward-Prowse's mindless sending off.
The touchline fracas lit the blue touch paper for a Sunday slugfest in the closing stages. Colwill and Williams came to blows in the aftermath of Cucurella tumbling into his manager Maresca as tensions boiled over.
Palmer's deft touch presented him with the chance to score but Sels was twice equal to his efforts. Then it was Sanchez's turn to justify his No 1 status with a sublime save to claw away Williams' drive - and he was again called into action when Jota Silva met Ola Aina's cross to drag the ball away from almost behind him.
Nottingham Forest striker Chris Wood:
"We had chances to win it. I think we nullified them to a lot of things. Matz Sels was unbelievable in goal, made some great saves, kept us in the game and gave us the chance to win the game. That's what we're about, fighting to win.
"We know they're a good side, coming to the Bridge will always be a tough occasion. It shows the resilience we're trying to deliver and we want to continue and go bigger in the future and rise up the table. We want to be competing in the top half of the table and beyond. We take the positives and move on.
"It's always nice to be scoring the goals. It was nice to give us the lead, it would be nice to be three points rather than one.
"We want to bring these results to the City Ground, but it's nothing to panic about. we're playing good football and doing extremely well and it will click at home, there's no doubt about it."
Chelsea goalkeeper Robert Sanchez to :
"It was an end-to-end game. Both goalkeepers got called into a lot of action. But for me personally, it was a quiet game. I didn't touch the ball much.
"The team did everything it was supposed to do to get the chances, but it wasn't to be.
"For me and Sels, this is what's difficult about being a goalkeeper, you don't do much in the whole game, then minute 80 you have two big shots to save.
"We knew they weren't going to jump at us. But we knew we couldn't give them the ball and we didn't give them many chances. We deserved more and created chances but we didn't score the goal to get the points."