Despite the 1-0 victory against Burnley, Forest are still four points from safety with just two games still to play.
But at least they still have an outside chance of overhauling Brighton and Crewe and avoiding the drop into third tier of English football for the first time in over 50 years.
It could have been a very different story though as the visitors had enough chances to seal Forest's fate.
With 30 minutes gone Lee Roche crossed for James O'Connor, but he could only direct his header straight at home goalkeeper Colin Doyle when it looked easier to score.
Roche then had his own chance to break the deadlock, but his header from Mo Camara's centre was comfortably dealt with by Doyle.
Scott Dobie and Commons missed the target as Forest took control, before Paul Evans' long-range effort was caught by Clarets keeper Danny Coyne.
After the break Ade Aknibiyi was twice presented with chances to give the visitors the lead by Camara, but headed the first wide before Doyle made a fine block from the second.
With 20 minutes remaining Gareth Taylor found John Curtis in space on the right flank and his cross was flicked on by Dobie. Commons ran on to the loose ball and blasted home to give Forest a vital lead.
The Clarets were unable to find an equaliser and Crewe's defeat by Stoke made sure it was a successful afternoon for Megson's men.