Nadir Vassena studied composition in Milan with Bruno Zanolini and Alessandro Solbiati, and then in Freiburg with Johannes Schöllhorn. In 1993, he studied with Brian Ferneyhough and Joël-François Durand at Royaumont. The following year, he undertook study of electronic music with Alvise Vidolin at the Scuola civica in Milan and at IRCAM. In 2000-2001, he was composer-in-residence at Schloss Solitude in Stuttgart, and in 2002, he was a student at the Denkmalschmiede Höfgen/Margarethen Foundation and a member of the Swiss Institute in Rome. His works have been performed on multiple occasions at Gaudeamus Muziekweek. Vassena has been the recipent of numerous prizes, such as at the WDR Cologne Young Composers Forum, for Per una maschera (1992); a first prize from the Institut für Neue Musik at the Berlin Hochschule, for Nocturnes I-II-III (1994); first prize in the Winterthur Competition for Young Composers of Chambre Music for Formulae (1996); the Pro Helvetia Prize for Amras-Turm Fragmente (1996); second prize in the "Mozart in Salzburg" Competition (1997); first prize in the Besançon International Orchestral Composition Competition (1998); and first prize from the Christoph Delz Foundation in Basel (1999).

Vassena had several noteworthy premieres in 2009: Altri infidi luoghi, by Vocaallab Nederland at the Gaudeamus Festival; Coreografie incerte at the Conservatorio della Svizzera Italiana; and Cinque stanze buie at the Pianoforte Foundation in Chicago.

He has taught composition and analysis at the Conservatorio della Svizzera Italiana in Lugano since 2004. He was a member of the artistic committee of the RepertorioZero Association in Italy from 2008 to 2010, and served as Director of the Tage für Neue Musik Festival in Zurich with Mats Scheidegger.