John Nuzzo, a year-old Mill Valley resident who died from an apparent heart attack at his home Sunday, was better known to legions of fans as John Leslie, the groundbreaking adult-film actor who appeared in more than movies before becoming a prolific director. Nuzzo made his initial mark during the industry's so-called Golden Age of budgeted big-screen films, notably in 's "Talk Dirty to Me," when he unofficially succeeded John Holmes as porn's most famous leading man. Pornography was made for John Leslie. As a young man, Mr.