William Troost-Ekong had given Nigeria the lead in the first half with a header from a dangerous corner routine. A front-post scramble between several players saw the original delivery loop into the air, and the Nigeria captain leapt to head the ball into the net.
Franck Kessié equalised from an Adingra corner in the 62nd minute, before Haller’s late intervention decided the fate of the tournament.
It marks Ivory Coast’s third AFCON triumph, bringing them level with Nigeria as the joint-fourth most successful team in tournament history, and first since 2015. Only Ghana (4), Cameroon (5) and Egypt (7) have more. It is the fifth time Nigeria have fallen short at the final hurdle of the competition.
FIFA president Gianni Infantino was in attendance at the final, as was Ivory Coast legend Didier Drogba.
The result is all the more remarkable given Ivory Coast’s victorious coach, Emerse Faé, only took over as coach after the group stage. Veteran Frenchman Jean-Louis Gasset was the manager at the start of the competition, but saw his team lose two of three games in that preliminary round to fall to the brink of elimination.
However, Nigeria took the lead against the run of play in the 38th minute through Troost-Ekong’s header, the Super Eagles’ first effort on goal of the match.
Ivory Coast almost hit back early in the second half, when a bouncing ball fell to the feet of Max Gradel at point-blank range — only to see his effort locked by the left leg of Calvin Bassey and roll harmlessly into the hands of Stanley Nwabali.
Eventually the pressure told, with Ivory Coast scoring from a corner of their own to square proceedings and send the entire stadium — including Drogba — into rapturous celebrations. Kessié took advantage of some suspect marking to direct a corner goalwards, and it slipped through the hands of Nwabali into the bottom corner.
Haller scored the all-important goal after Adingra beat Ola Aina and delivered a pacy cross. Haller, whose career was paused by a cancer diagnosis just over 18 months ago, met the cross from the left with an deft touch which arrowed into the bottom right corner of the net.
Nigeria threw caution to the wind for the rest of the game, with Portuguese coach José Peseiro sending on several attacking substitutes to support Victor Osimhen, who toiled up front on his own for large swathes of the hot evening.
But the hosts’ defence held firm to secure a famous victory that no doubt will have Abidjan and beyond partying long into the night.