made his Bellator debut on September 30, 2010, at Bellator 31, where he defeated Scott Stapp via TKO in the first round. The fight was contested at a catchweight for Chandler to test himself for the lightweight division, all his previous bouts being in the welterweight division.
In his next Bellator appearance, Chandler fought on the Bellator 32 card against Chris Page in a welterweight contest. Chandler won the fight in the opening minute via submission (guillotine choke).
In February 2011, Bellator announced that Chandler would be a part of the Bellator Season 4 Lightweight Tournament. In the opening round of the tournament, Chandler fought Polish prospect, Marcin Held, at Bellator 36. Chandler won via technical submission after choking Held unconscious with an arm-triangle choke.
The win moved Chandler into the semi-finals. Chandler then fought Lloyd Woodard at Bellator 40 and won via unanimous decision to move onto the finals of the tournament.
The tournament final took place at Bellator 44 where Chandler would face Team Nogueira product, Patricky Freire. Chandler utilized his wrestling skills, repeatedly taking down Freire and controlling the fight. He defeated Freire via unanimous decision (29-27, 29-27, 29-27) to win $100,000 and a shot at the Bellator Lightweight Championship versus Eddie Alvarez.
Chandler was expected to compete for the Bellator Lightweight Championship at Bellator 54. However, Alvarez suffered an undisclosed injury and forcing the bout to be postponed until a later date. Chandler/Alvarez was rescheduled to take place on November 19, 2011 at Bellator 58. Chandler defeated Eddie Alvarez winning by rear naked choke in the fourth round. Chandler came in very aggressive in the first and second round. In the third round, Alvarez landed several shots stunning Chandler. In the fourth round, Chandler dropped Alvarez with a punch, took his back and forced the tapout.
In his first fight after winning the title, Chandler faced Japanese veteran Akihiro Gono in a non-title superfight at Bellator 67.He won the fight via TKO at just 56 seconds into the first round.