Middleweight Nunn turned professional in 1984. After winning his first thirty fights, he fought IBF middleweight title-holder Frank Tate, who was 23-0. The fight took place on July 28, 1988 at
Caesars Palace in Las Vegas. Nunn won the title by a ninth-round knockout. In his first title defense, he knocked out
Juan Roldan in the eighth round. His second defense was a stunning first-round knockout of
Sumbu Kalambay to capture the vacant lineal middleweight championship. Nunn's next two title defenses were twelve-round majority decision wins over
Iran Barkley and
Marlon Starling. For his fifth defense, Nunn went to
France and knocked out
Donald Curry in ten rounds. On May 10, 1991, in his hometown of Davenport, Iowa, Nunn lost his title in a big upset to
James Toney. Nunn, well ahead on points after ten rounds, was knocked out after being dropped by a left hook in the eleventh round.
Super middleweight After the loss, Nunn moved up a weight division to
super middleweight and won the NABF title with a tenth-round stoppage against Randall Yonker. On September 12, 1992, Nunn won the WBA and lineal super middleweight titles with a controversial twelve-round split decision over
Victor Cordoba. The WBA ordered a rematch, which took place on January 30, 1993. Nunn fought much better in the rematch, winning by a one-sided twelve-round unanimous decision. In his fifth title defense, Nunn lost the title to
Steve Little by a twelve-round split decision on February 26, 1994, in another huge upset. On December 17, 1994, Nunn traveled to
Ecuador to fight
Frankie Liles in an attempt to regain the lineal and WBA super middleweight titles. In a very close fight, Liles, who had defeated Little in his previous fight to win the title, defeated Nunn by a twelve-round unanimous decision.
Light heavyweight After nine consecutive wins, Nunn got another title shot. On March 21, 1998, he fought
Graciano Rocchigiani for the vacant WBC
light heavyweight title in
Germany. Nunn lost by a twelve-round split decision, with the judges favouring Rocchigiani's fewer, more solid punches over Nunn's much higher volume of lighter shots. On January 23, 2002, Nunn defeated Vinson Durhan by a ten-round unanimous decision at
Caesars Indiana in Bridgeport, Indiana. It would be his last fight. He finished with a record of 58-4 with 37 knockouts. ==Arrest and sentencing==