Biles, a star member of the USA's successful gymnastics team at the 2016 Rio Olympic Games, on Monday became the latest athlete to state that she was molested by Nassar.
Nassar was last month sentenced to 60 years in a federal prison for having child sex abuse images on his computer.
He is also awaiting sentencing after pleading guilty to seven counts of criminal sexual conduct in November.
Biles tweeted a statement which said: "Most of you know me as a happy, giggly and energetic girl. But lately… I've felt a bit broken and the more I try to shut off the voice in my head the louder it screams. I am not afraid to tell my story anymore.
"I too am one of the many survivors that was sexually abused by Larry Nassar. Please believe me when I say it was a lot harder to first speak those words out loud than it is now to put them on paper.
"There are many reasons that I have been reluctant to share my story, but now I know it is not my fault.
"It is not normal to receive any treatment from a trusted team physician and refer to it horrifyingly as the 'special' treatment. This behaviour is completely unacceptable, disgusting, and abusive.
"For too long I've asked myself, 'Was I too naive? Was it my fault?' I now know the answer to those questions. No. Not, it was not my fault. No, I will not and should not carry the guilt."
Biles' former team-mate Gabby Douglas and fellow Olympian Aly Raisman have also accused Nassar of abuse.
When contacted by Omnisport, Nassar's attorney declined to comment on Biles' statement.
— Simone Biles (@Simone_Biles) January 15, 2018
USAG released a statement, saying: "USA Gymnastics is absolutely heartbroken, sorry and angry that Simone Biles or any of our athletes have been harmed by the horrific acts of Larry Nassar.
"USA Gymnastics' support is unwavering for Simone and all athletes who courageously came forward to share their experiences.
"We are our athletes' advocates. USA Gymnastics will continue to listen to our athletes and our members in our efforts of creating a culture of empowerment with a relentless focus on athlete safety every single day."
Photo Getty Images. Caption: Four-time Olympic gold medallist Simone Biles