Michail Antonio netted with a first-half header to give Stuart Pearce's side a 1-0 lead at the break, before they stepped up a gear in the second half, with Antonio prodding home a second in the 47th minute before setting up Matty Fryatt for a headed goal six minutes later.
It took the former Sheffield Wednesday man's tally to four for the season - and B#5million striker Britt Assombalonga was not to be outdone, notching his fourth of the campaign from close range to cap off victory in the 64th minute.
Forest's win maintained their unbeaten start to the campaign - and also their position at the top of the table.
Adam Federici had to produce a smart double save to deny Forest a goal as Andy Reid pounced on a kind deflection, with the keeper diving in bravely at his feet before swiftly recovering to repeat the manoeuvre at the feet of Chris Burke.
It was the first time Forest had seriously threatened the Reading goal, but they took the lead with their next meaningful attack, courtesy of a familiar combination, as Burke delivered a fine cross from the right flank, picking out Antonio, who powered home a header off the underside of the bar.
Jordan Obita had denied Forest a second goal when he headed clear off his own line, after Danny Fox had powered a header into the danger zone, with Fryatt then prodding the loose ball wide of the post.
Forest did survive two scares, with Aaron Kuhl poking wide from a good position 10 yards out - and former Forest man Simon Cox failing to make the most of a better chance, sending a bobbling shot the wrong side of the far post.
The home side all but secured three points within eight minutes of the restart, with two goals in quick succession. The first came in the 47th minute as Jack Hunt advanced down the right to deliver a looping ball to the far post, where Antonio was arriving again, this time to squeeze home a prodded shot, from close range.
Six minutes later Antonio turned provider, cutting inside onto his right foot to lift a cross enticingly into the path of Fryatt, who lapped up the opportunity, powering home a header beyond the helpless Federici.
Reading were shell-shocked - and Forest were rampant, with a fourth goal coming in the 64th minute, following a melee in the goalmouth. The Royals struggled to clear following a shot from Antonio, with Assombalonga eventually pouncing to drive into the back of the net.
It might have been 5-0 when substitute Jamie Paterson drove in a shot from 12 yards after Reading again failed to clear, if not for a fine reaction stop from Federici.
Federici produced another outstanding save to deny substitute Eric Lichaj after he fired in a shot from 25 yards - and skipper Chris Cohen lashed wide when the ball fell to him from a corner.