With deals confirmed for striker Rafik Djebbour and left-back Danny Fox and international clearance awaited for central defender Kevin Gomis, 18,510 at the City Ground and a TV audience watched Watford take a two goal lead thanks to a brace from Angella.
Half-time substitute Simon Cox sparked the hosts into life, however, his goal on 58 minutes leading to a sustained spell of pressure which saw fellow substitute Darius Henderson draw Forest level.
Billy Davies then threw Jamie Mackie into the fray and he took just two minutes to join his fellow subs on the scoresheet and give the home side a lead which Cox extended in the final minute of the game.
Forest move seven points clear of the teams outside the play-off places as, with more signings potentially to come on Friday, a slow burner of a week ends with a bang.