Both sides had penalties saved before David Luiz notched a 39th minute spot-kick and Torres doubled the advantage just before the break.
Joshua John pulled a goal back for the visitors soon after the re-start but Gary Cahill restored the advantage on 51 minutes and Torres, Juan Mata and Oscar goals completed the rout.
But Juventus beat Shakhtar 1-0 in Group E's other game to mean Chelsea go into the Europa League as third placed finishers.
Victor Moses saw his early volley saved by Jesper Hansen, while the Nordsjaelland keeper then got down well to deny Torres.
Chelsea then hit the bar when Nordsjaelland skipper Nicolai Stokholm hit a Moses' cross onto the woodwork.
Nordsjaelland won a penalty when Anders Christiansen's shot hit Gary Cahill's arm but Petr Cech saved from Stokholm.
At the other end, Hansen saved a spot-kick from Eden Hazard after Cahill's header from a corner hit substitute Mikkel Beckmann on the arm.
But Luiz made no mistake from the spot-kick soon afterwards after Juan Mata's effort also hit Patrick Mtiliga on the arm.
Torres doubled the advantage just before the break before John got a goal back from a pass from Kasper Lorentzen soon after the re-start.
Cahill headed home Juan Mata's free-kick on 51 minutes and Torres got his second of the night five minutes later when notching from Hazard's pull-back.
Mata scored on 63 minutes and substitute Oscar added a sixth on 71 minutes to complete the rout but Juventus won against Shakhtar to deny the Blues passage into the last 16 and Rafa Benitez's side now go into the Europa League.