A stage actor by the late '30s, Nicol began acting in films in 1950. He appeared in numerous films, including Anthony Mann's Strategic Air Command and The Man from Laramie and began directing in 1958 with the horror tale The Screaming Skull; he also helmed the war drama And Then There Were Three and the thriller Point of Terror. Nicol's other memorable films as an actor include Martin Ritt's Five Branded Women, Don Chaffey's A Matter Of WHO, and Roger Corman's Bloody Mama.