Forest continued to grow into the game and weighed in with several dangerous chances, though West Brom also had a handful of opportunities to break the deadlock in the first half.
Neither side could open the scoring come the break, but first blood ended up being drawn by Aitor Karanka's side just before the hour mark.
Adlene Guedioura picked up the ball 25 yards from goal, took a touch forward and unleashed a ferocious drive which took a slight deflection from Bartley en route to the back of the net.
The Algerian then came close to scoring a wonderful second from his own half after spotting Sam Johnstone off his line, but the Albion goalkeeper managed to get his fingertips to the ball.
A frantic finish to proceedings, which included West Brom hitting the post twice and Grabban seeing a header cleared off the line, saw the visitors nab an 87th-minute equaliser.
NOTTINGHAM FOREST (4-2-3-1): Pantilimon; Darikwa, Figueiredo, Fox, Osborn; Guedioura, Colback; Dias (Goncalves 77'), Carvalho (Soudani 85'), Lolley; Grabban
WEST BROMWICH ALBION (4-2-3-1): Johnstone; Adarabioyo, Bartley, Hegazi, Gibbs; Livermore, Brunt; Phillips, Morrison (Gayle 61'), Barnes'; Rodriguez (Robson-Kanu 90')