From Wikipedia

Nadine Ruth Mix (July 13, 1912 - September 21, 1977) was the daughter of western film star Tom Mix, and a B-movie actress during the 1930s.

Born in Dewey, Oklahoma, to Tom and Olive Stokes Mix, she started her acting career following in her father's footsteps. In the mid-1920s she starred in several silent films. She made a total of twelve westerns, particularly The Tonto Kid, Fighting Pioneers, Saddle Aces and Gunfire, all made in 1935. In 1936 she starred in three cliffhanger serials, The Black Coin, The Amazing Exploits of the Clutching Hand, and Custer's Last Stand.

She played the female lead in a few B-westerns, starring alongside Wally Walls and Hoot Gibson. She then retired from acting and began taking the lead role for her father's circus and wild west show.