"Nostálgico" (transl. "Nostalgic") is a song produced by Jamaican record producer Rvssian and recorded by Puerto Rican singer Rauw Alejandro and American singer Chris Brown. It was written by Lionchild, Brown, Eric Bellinger, Ben Shapiro, Feli Ferraro, Richard McClashie, Teezio, Colla, Kenobi, Alejandro, and Rvssian, while the production was handled by Rvssian. The song was released for digital download and streaming as a single by Sony Music Latin and Head Concussion Records on September 8, 2021. A primarily Spanish language R&B-infused reggaeton and dancehall song, it reminisces on a past relationship that the singers want back. The track received widely positive reviews from music critics, who complimented its Caribbean beats and the singers' exchange of verses.
"Nostálgico" was nominated for Crossover Collaboration of the Year at the 2023 Premio Lo Nuestro. The song was commercially successful, reaching the top five in Puerto Rico and Spain, as well as the top 10 in several other countries such as Dominican Republic and Peru, and on Billboard's Latin Airplay in the United States. It also peaked at number 11 on the US Billboard Hot Latin Songs chart. The song has received several certifications, including Latin quintuple platinum in the United States. An accompanying music video, released simultaneously with the song, was directed by Edgar Esteves and depicts the three musicians partying at a sensual house party.