Nolan was my idol when I was pitching as a kid in the late 80's/early 90's. There were several reasons for his longevity. He had great mechanics using his legs and hips along with his shoulders. He also only had 3 pitches- fastball, curveball, and a circle change. He did not torque his elbow throwing his curveball. He slightly changed his grip and adjusted his wrist angle, which prevented stress on the elbow. Unbelievable pitcher and competitor.Some people are built different, Nolan was one of those. Also, he didn't have the wear and tear early in life from playing travel ball age 5-16.
For those interested, watch this 3 minute video.