Monzón signed for Vélez Sarsfield in 2015, going on to score over forty goals in their academy.[5][6]Mauricio Pellegrino promoted the centre-forward into his first-team squad in 2020, as he made his senior debut on 28 October in a Copa Sudamericana second stage first leg draw at home to Peñarol; he replaced Pablo Galdames for the final moments.[4][7] He went unused on the substitute's bench seven times across the next month or so, prior to making his bow domestically off the bench on 5 December in the Copa de la Liga Profesional versus Patronato.[4] Monzón's first goal arrived on 16 January 2021 versus Rosario Central.[4] In July 2021, Monzón joined Platense on a loan for the rest of the year.[8] On 26 January 2022, Monzón was loaned out again, this time to Almirante Brown until the end of 2022.[9]
International career
In 2019, Monzón received a call-up from the U18s for the COTIF Tournament in Spain.[5] He scored once, in a five-goal victory over Bahrain, as they placed third.[5][10]