 Nava began his career in 1985 with Pro Sesto, before joining the Milan Youth Squad.In 1988, he made his professional debut in Serie C1 with Virescit Boccaleone, and during the next season, he moved to Serie B side Reggiana.He returned to Milan in 1990, where he was a reserve in the first team's defence, behind the legendary Maldini, Baresi, Costacurta, Tassotti back-line, which is regarded by many as the sport as one of the greatest defensive line-ups of all time.