"It was a good game, they were better in the first half but I thought we were a lot better in the second and were pretty dominant," said Calderwood, who took charge at the City Ground in the summer.
"It was an excellent point, but I was just waiting for those half chances and if I'm being really honest I thought we were going to score because we looked a real threat."
The top three teams - Scunthorpe, followed by City and Forest - are only seperated by goal difference.
"It's exciting now it's getting concertinaed at the top and to get a draw away from home at one of your promotion rivals is something to be positive about," added Calderwood.