Nugent became the first City player to score a treble against the Tigers since Arthur Rowley in 1952, as Nigel Pearson’s team swept his former charges aside to register a fourth successive win on their own patch.
The former Portsmouth and Preston forward was the spearhead for an outstanding team performance. He scored the Foxes’ maiden first-half goal of the season with his left foot on seven minutes and, after Jay Simpson’s equaliser, regained the lead with his head shortly before half-time.
And at the end of a second half that saw Pearson’s men dominate possession and dictate the pace of the game authoritatively, Nugent slotted a breakaway third with his right foot to complete a perfect hat-trick – the first of his career.
The three points were a just reward for a superb display from the Foxes, who rise to seventh in the table ahead of next Saturday’s trip to eighth-placed Middlesbrough.
After an energetic start, City broke through in the seventh minute as Nugent slotted past Ben Amos, intercepting Danny Drinkwater’s shot before coolly slotting past Ben Amos in the Tigers goal.
And they could have doubled their lead had it not been for Hull’s back line, as Jamie Vardy saw two attempts thwarted - a superb Amos save and an Abdoulaye Faye goal-line clearance halting the striker.
Hull showed just why they were occupying a play-off position midway through the first half. With the Blues still chasing a second goal, the Tigers struck.
Sone Aluko, who looked lively in possession throughout the opening stages, fizzed a ball into City’s box for Simpson to latch onto and the former England Under 21 forward netted the equaliser in the 26th minute.
An even 20 minutes followed, with both sides scrapping in possession and having half-chances to take the lead. As the first half was heading into its final stages, Nugent netted his second of the match to switch the advantage to the Foxes.
The instrumental Anthony Knockaert raced down the right wing and chipped a ball towards Nugent, who nodded past Amos three minutes before the break.
Leicester began the second half as they did the first. An early attack could have seen them extend their lead, but as Knockaert slid in Vardy deep in the Hull area, the striker’s powerful shot again failed to beat Amos who performed another last-ditch save.
Kasper Schmeichel was called into action moments later, palming a long-range effort from Aluko past his left upright to maintain his side’s narrow lead.
Knockaert’s attacking persistence nearly bagged him a deserved goal as he found himself free 20 yards from goal.
The Frenchman’s low left-footed drive forced a fumbled save out of Amos 10 minutes from time, but failed to beat the on-loan Manchester United goalkeeper, who collected the ball at the second attempt. City’s summer signing from French side Guingamp proved his quality throughout the match.
Hull boss Steve Bruce was then sent to the stands following an incident with the assistant referee in front of the dugouts, as his side were pulled up on the counter attack as they tried to find an equaliser.
A frantic start to stoppage time saw City go from the verge of conceding a heart-breaking equaliser to the ecstasy of netting a clinching third, with Knockaert and Nugent heroic at either end.
Ahmed Elmohamady thought he’d equalised when he headed a corner from the right goalwards, only for Knockaert to clear off the line.
Substitute Martyn Waghorn carried the ball on a three-v-one counter-attack, playing in fellow substitute Lloyd Dyer on the right wing.
Dyer unselfishly squared the ball to the unmarked Nugent and the frontman calmly netted past Amos to complete his hat-trick in the 91st minute.
The result bumps the Foxes up eight places in the nPower Championship, just one point behind the play offs, making it four wins out of four in the league at the King Power Stadium this season.
City (4-2-3-1): Schmeichel; De Laet, Morgan (c), St. Ledger, Konchesky; James (King 70), Drinkwater; Vardy (Waghorn 74), Knockaert, Marshall (Dyer 85); Nugent.
Unused subs: Whitbread, Logan, Schlupp, Futacs.
Goals: Nugent 7, 42, 90+1
Hull (3-5-2): Amos; Chester, Faye (Proschwitz 78), Bruce; Elmohamady, Koren, Evans (Olofinjana 78), Quinn, Dudgeon (Rosenior 70); Aluko, Simpson.
Unused subs: Oxley, Dawson, McShane, Mclean.
Goals: Simpson 26
Attendance: 20,815 (1,482 away)