 He made his debut in the league on 14 August 2011, coming on as a 61st-minute substitute against Deportes Puerto Montt.Millán then got his first goal for Naval in the 3-1 win over San Marcos de Arica on 13 November 2011.In November 2012, it was announced that Millán was joining Unión Temuco for the 2013 season on a free transfer following the expiration of his contract with Colo Colo after the conclusion of the 2012 season.