The first effort on target came after 36 minutes when Eddie Lewis took a left-wing corner and played a one-two with Chris Sedgwick before hitting a left-foot shot from 15 yards which was tipped over the bar by Neil Alexander.
Lewis had been booked earlier for dissent and Youl Mawene was cautioned for a foul on Cameron Jerome after 39 minutes.
Peter Thorne had a shot saved by Carlo Nash on the stroke of half time but a scrappy first half ended goalless.
After 53 minutes Richard Cresswell had a shot blocked and the rebound fell to Sedgwick whose shot was saved and the ball was scrambled clear.
Lewis has a 15-yard shot saved by the Cardiff City goalkeeper who dived to his left and Cresswell put the rebound wide of the post.
Nugent made it 1-0 in the 67th minute when he hit a 20-yard half-volley into the top right-hand corner of the net giving the keeper no chance.
And Nugent made it two after 78 minutes when he hit a right-foot shot from 15 yards that flew into left-hand corner after a pin-point Cresswell cross.
Cresswell made it 3-0 to Preston after 84 minutes when he robbed substitute Willie Boland before hitting a 12-yard shot into the bottom right-hand corner of the net.