The first-half effort was enough to send the Vicarage Road side to their sixth win in seven games, strengthening their promotion push.
It was a first goal in 13 months for the Italian, and while Munoz was happy with his player, he was planning on giving him a more attacking role in the future.
He said: "Masina is a big player, right now he's in a good moment. Now is the time to push to change different things, but most importantly he has very good ambition.
"He wants to give the best for the team, sometimes he thinks more about the team than the individual .
"I'm happy with him, we've tried him more in attack and we want to see him in offence.
"I want to say congratulations to the players, I know we have done very hard work, but I think we can be better and have more control of the game.
"I think I have a very good squad, and right now it doesn't matter who I put in the first 11, everyone is in the high level."
After finding the net twice in midweek, Andre Gray nearly added his third of the week after just four minutes when he connected to a cross by Kiko Femenia, but his effort was collected by goalkeeper Brice Samba.
The home side continued to have the majority of the early play, and they took the lead on 17 minutes.
With one goal still separating the sides, the visitors were still very much in the contest, and Bong headed wide on 72 minutes after an Anthony Knockaert cross.
Zinckernagel could have settled the contest on 77 minutes, but his effort was directed over the crossbar.
Former Watford midfielder James Garner scuffed an effort wide for the visitors with three minutes remaining, while a shot from substitute Lyle Taylor that found the target was ruled offside.
It was enough for Watford, though, while Nottingham Forest failed to rebound after their defeat against Luton last week.
Manager Chris Hughton believed the quality in the final third proved to be the difference between the two sides.
He said "There wasn't a lot in it, and that's one thing I continue to speak to the players about – we look at why Watford are where they are and we are where we are.
"That's the difference. We've had games against top six where the level of performance has been good and not too far away from the opposition.
"But it's finding the way to get that win. That's what the top teams do, and unfortunately that was the case today.
"They've got the goal today and probably in the final third they look more threatening. The difference is they find a way of winning."