On May 29, 2012 Nelson signed a 1-year long contract with Cartaginés. Nelson made his debut for Cartaginés in the opening match in the Winter 2012, against Belén Siglo XXI playing the whole game. On 7 August, Nelson made assistance for the tie against Limón in Cartaginés 1-2 victory, after Hansell Arauz recovered the ball in 3/4 of field, passes to Nelson, running and leaves two opponents to make an assistance to Erick Ponce. On 28 October, Nelson created a play of a wall with Randall Alvarado, made attendance goal to Paolo Jimenez, in the game who lost Cartaginés 1-3 against C.D. Saprissa. On 7 November, he made a goal assisted by Eduardo Valverde in the game who lost Cartaginés 2-3 against C.S. Herediano.
