Grant Leadbitter marked his home debut for Town with a goal after 42 seconds but Blues had to settle for a point.
The transfer deadline day signing from Sunderland fired in the far post in Blues' first attack but Forest left with a point after Rob Earnshaw announced his arrival as a second-half substitute with the equaliser seconds after he came on.
Town were reduced to 10 men in added on time when Gareth McAuley pulled down Dele Adebola on the edge of the box as he raced in on goal.
Blues made three changes to the side that went down at Middlesbrough at the weekend, Alan Quinn, Jon Stead and Lee Martin coming in with Jack Colback, Jaime Peters and Pablo Counago dropping to the bench.
Blues got off to the perfect start, Leadbitter pouncing from six yards after Stead had headed on Carlos Edwards' throw on.
Joe Garner responded for Forest with a shot over the bar, Alan Quinn following with a similar effort as the game kicked off at a frantic pace.
Stead forced a corner that was hacked clear by Wes Morgan as Alex Bruce threatened, Martin then picking up the first yellow card of the game for a push.
Richard Wright had an anxious look over his shoulder after Liam Rosenior's clearance cannoned back off Dexter Blackstock and drifted just wide of the Town goal from 40 yards, Jon Walters then testing Lee Camp from distance.
Garner was yellow carded by referee Gavin Ward for a foul on Martin, Stead heading the free-kick wide while at the other end, David McGoldrick dragged his shot wide from a good position.
The best move of the first-half ended with Gareth McAuley bringing down McGoldrick on the edge of the box, Chris Cohen sending his free-kick well over.
Town went close to extending the lead five minutes before the break when Rosenior and Edwards carved out an opening down the right, Edwards' cross flashing across goal.
Edwards tried an audacious effort from an acute angle in the last opening of the half that saw Leadbitter and Chris Gunter booked for fouls.
Dele Adebola replaced Blackstock, who took a knock to his head early on, at the break in the first change of the game, the experienced striker joining McGoldrick up front.
Delaney sent a right footer a yard wide in the first strike in anger of the second-half, Town then having a quick look at the referee as Forest appealed for handball as Bruce dived low to clear on the edge of the box.
Cohen saw a free-kick deflected wide after Martin had been penalised before Forest made a second change, former Norwich striker Earnshaw getting a 'warm' reception as he replaced Garner.
The Wales international silenced Blues' fans though within 30 seconds of coming on, bursting into the box and beating Wright with a right foot finish into the roof of the net.
Colback and Peters replaced Edwards and Quinn as Town boss Roy Keane freshened up his midfield on the hour.
Peters was soon in the action, drifting past two defenders before seeing his effort deflected wide. Adebola then booked for timewasting.
Liam Trotter replaced Rosenior for the final 20 minutes, Town enjoying a flurry of corners, initially following a great run by Leadbitter.
McGoldrick fired across goal after cutting inside Bruce, Forest then making a final change with Paul Anderson making way for Garath McCleary. McGoldrick was booked for attempting to take Leadbitter's shirt off his back as the yellow cards mounted up.
Colback fed Martin on the right flank, the former Manchester United midfielder firing wide of the far post as Town pressed for a second goal
Gareth McAuley saw a header kicked off the line by Gunter, Colback then booked for an apparent dive with Town claiming a penalty as the game entered the last five minutes.
Blues lost McAuley to a red card in added on time after he lost possession to Adebola and pulled the striker down as he went in on goal, the draw leaving Blues still searching for that elusive first win in the Championship this term.
Town: R.Wright, Rosenior (Trotter 71), McAuley, Bruce, Delaney, Edwards (Peters 60), Quinn (Colback 60), Leadbitter, Martin, Stead, Walters. Subs not used: Lee-Barrett, Counago, Priskin, Smith. Sent-off: McAuley. Booked: Martin, Leadbitter, Colback.
Forest: Camp, Gunter, Chambers, Morgan, Lynch, Garner (Earnshaw 57), McKenna, Cohen, Anderson (McCleary 75), McGoldrick, Blackstock (Adebola 46). Subs not used: Smith, Wilson, McGugan, Moussi. Booked: Garner, Gunter, Adebola.
Att: 21, 130



















