Nicolás José Posse (born 4 February 1965) is an Argentine politician and industrial engineer who was the country's Chief of the Cabinet of Ministers from December 2023 to May 2024 under president Javier Milei.

[2] Posse attended the Instituto Tecnológico de Buenos Aires, graduating in 1989, and the University of Cambridge.

[3] Posse began his career at Molinos Río de la Plata, before working as the CEO of duty-free sales at Aeropuertos Argentina 2000, a subset of Eduardo Eurnekian's Corporación América.

In the libertarian campaign, Posse was in charge of leading the technical teams of La Libertad Avanza.

After Milei's electoral victory, Posse coordinated the transition and was present at the first meeting between president-elect Milei and outgoing president Alberto Fernández at Quinta de Olivos to discuss the transfer of command.