For which film did Jack Nicholson gain his first Oscar nomination?

Explanation

Jack Nicholson has been nominated for an Oscar no less than 12 times, and has won thrice. His first nomination was for his role in the film 'Easy Rider' from 1969, but it was not until 1976 that he won his first Oscar, for his performance in the film 'One Flew Over the Cuckoo's Nest'.