United have 59 points from 30 games, three points in front of fourth-placed Newcastle United and six ahead of Tottenham Hotspur, who have played 31 matches.
Steve Cooper's struggling Forest side, who are now without a win in 10 consecutive league games, are third from bottom, level on 27 points with 17th-placed Everton.
Dalot found the net in the 76th minute, scoring his first Premier League goal in his 100th appearance for United, running onto a pinpoint through ball from Antony.
UNITED CALM"Inside the dressing room, I think we were calm," added Dalot.
Navas ensured the result was not more emphatic with a string of fantastic saves in a game dominated by United.