Millwall 1-3 Leicester City
Leicester maintained their four-point lead at the top of the Championship after beating managerless Millwall.
Anthony Knockaert opened the scoring with a low strike.
Despite chances for Millwall pressure Nugent headed in from close range to extend Leicester's advantage.
Richard Chaplow grabbed a goal back for Millwall but Jeffrey Schlupp added another goal in injury time as Leicester recorded their fourth consecutive win to stay above Burnley.
After Sheffield Wednesday's win over Blackpool, Millwall are now only a point above the relegation zone and have lost four of their last five matches.
The Foxes have won 12 of 14 games when scoring first, and once more highlighted deficiencies in the Championship's worst defence when Knockaert retrieved the loose ball in the centre of Millwall's half, and drove untroubled at the Lions defence to fire in a low shot.
But, that chance aside, Millwall were the team in charge.
Kasper Schmeichel twice punched away well-struck shots, first from Nicky Bailey then Chaplow and also saved Scott McDonald's effort.
But all Millwall's work was undone by another early goal in the second half - this time within three minutes.
Gary Taylor-Fletcher provided the assist, running onto Lloyd Dyer's pass and luring David Forde wide of his goal, before setting up Nugent for the easiest of his season's 12 league goals - an unmissable, one-yard header.
Millwall were again on the front foot when they grabbed a first goal in four games.
McDonald created the opportunity bustling through the left channel and forcing a reactionary save from Schmeichel. However, Chaplow just reached the loose ball first and slammed home his first Millwall goal.
Substitute Jermaine Easter had one glorious opportunity to vindicate his introduction, but fired his shot several rows into the stand.
And with Millwall committing men forward in search of an equaliser, substitute Schlupp then burst through and slid his shot under Forde to seal the win.
Millwall caretaker boss Neil Harris:
"I'm disappointed for my players, I thought they were fantastic from the first minute to the last. Everything that was asked of them they have done, I thought we were better than the best team in the league.
"I thought [the referee] got two decisions wrong for two goals, looking back now, there are clearly two fouls.
"Myself and [academy director] Scott [Fitzgerald] will keep going until we are told otherwise and the board find the right man. The biggest thing for me is that I want the players to play with a bit of freedom and show what good players they are."
Leicester boss Nigel Pearson:
"The important thing is we try and build on the first half of the season and if you're going to have any success you've got to win in different ways. We've had good wins recently in a footballing sense, but the conditions today meant we couldn't do so much passing.
"There were a lot of mistakes, but the players showed a lot of strength. From our perspective it was good to show we can win a physical game, we made heavy weather of it in the second half but that was as much down to Millwall's approach.
"It's certainly better to be at the top than not, but it's always going to be tight. It's a tough ask to be consistently good, we found that out last year when we had an awful run through February and March, which probably cost us promotion."