Southend had given them a scare when Mark Gower gave them a third minute lead, but Forest hit back emphatically to claim a thumping 4-1 win.
Ian Breckin headed them level before the break and a mad ten minutes in the second half saw Southend concede two goals, from substitute Nathan Tyson and Junior Agogo, and have Leon Clarke sent off.
Agogo wrapped up victory by netting the fourth in the 86th minute.
Southend got off to the perfect start, as a mistake from Sammy Clingan sent Gower racing clear of the Forest defence and the winger took full advantage, maintaining his composure to bend a powerful finish beyond the advancing Paul Smith and inside the post from 18 yards.
But, after taking their third minute lead, the visitors found themselves on the back foot, as Forest immediately turned the screw in search of an equaliser.
Lewis McGugan tried his luck from 30 yards, but saw Steve Collis make a comfortable save. Kris Commons then failed to properly connect after being picked out by Chris Cohen, following his powerful surge into the box.
Forest were enjoying plenty of possession, but Southend still looked to be a threat on the break, with Alan McCormack screwing a half chance well wide, after finding space on the edge of the box.
Just when the home side's momentum seemed to have dropped, Cohen burst forward to win a corner and, although it was initially cleared, it fell to Clingan on the near side - and the Northern Ireland international made amends for his earlier error by delivering an inch-perfect ball back into the box for Breckin to head powerfully into the back of the net from six yards.
With his confidence restored, Clingan almost gave Forest the advantage before the interval as he let fly with a powerful drive with his left boot, forcing a capable stop from Collis who did well to hold the ball.
Forest began the second half in bright fashion with Luke Chambers crashing a header against the foot of the post after Clingan had delivered a well-flighted free-kick into the box.
Southend almost regained the advantage - and perhaps should have - as Leon Clarke headed badly wide from close range. But that was the turning point.
Forest introduced Tyson off the bench in the 62nd minute and it took the striker only two minutes to put the home side ahead, as he latched on to a through ball from Cohen before sliding an equally accurate finish into the bottom corner.
Two minutes after that and Southend were down to ten men as Clarke released his frustration by headbutting Chambers, sparking off a mass brawl and earning him a red card.
By the 72nd minute, Forest had the points wrapped up as Agogo fired home their third, finding the bottom corner of the net from 25 yards.
And the Ghana international rubbed salt into Southend's wounds by heading home Tyson's cross in the 86th minute.