Born in Miami, Florida, she is one of three children of former NBA star Norm Nixon and actress Debbie Allen.
On her final year of the Ailey/Fordham BFA Program in Dance, Nixon was cast as Kalimba in the Broadway production of Hot Feet, the classic storyline of The Red Shoes with a '70s funk facelift, and Kalimba is the ambitious girl at the center of it who can't stop dancing (literally).
On television, she had secondary roles in the Fox musical series Glee and NBC's Smash.
In 2015, she began appearing as Dr. Hannah Brody in the ABC medical drama series, Grey's Anatomy.
In December 2020, she began voicing Millie in the web series Helluva Boss in all episodes, except the pilot.