Toward the end of his life, Nash wrote site-specific compositions for public spaces in New York, such as Still Sounds Run Deep, in which musicians set themselves up in large areas: such as Battery Park's Castle Clinton or around the lake in Central Park: and performed, synchronizing the music with stopwatches and interacting with passersby and ambient sounds.

Nash, who grew up in the Bronx, attended Berklee College of Music and Mills College. In San Francisco he formed the Paul Nash Ensemble, and then helped form the Bay Area Jazz Composers Orchestra. The group applied for public grants with which to commission new contemporary works.

In the late 1980s, Nash returned to New York and formed the Manhattan New Music Project, which still exists, and which has presented 35 new works by such composers as Neal Kirkwood, David Taylor, and Bruce Williamson.

In addition, Nash was an arts advocate and created educational programs for New York public-school students.