At least 65 victims are set to confront Nassar in court this week in the last of three sentencing hearings, prosecutors say.
He was sentenced last week to 40 to 175 years in prison after nearly 160 women testified that he had molested them.
He was earlier sentenced to 60 years' prison for having child abuse images.
Wednesday's hearing is to sentence Nassar for molesting patients in the back room of Twistars gymnastics club in Dimondale, Michigan. He pleaded guilty in November to three counts of first-degree criminal sexual conduct against girls for whom he was supposed to be providing medical care.
At least one of the sexual assaults included a victim younger than 13. Two of the victims were abused at 15 or 16 years old.
Judge Janice Cunningham told the small court in Charlotte, Michigan: "We have over 265 identified victims and an infinite number of victims in the state, in the country, and all over the world.
"As a result, by allowing live streaming and tweeting, all individuals are able to participate in this process."
The first to speak at Wednesday's hearing was 17-year-old Jessica Thomashow, who said Nassar first molested her when she was nine.
"Larry Nassar is evil," she said. "Larry Nassar is a criminal of the worst kind."
USA Gymnastics has said every director of its board has now resigned in the wake of the scandal.
The US Olympic Committee demanded that the entire board step down by Wednesday or face losing their governing authority.
"We are in the process of moving forward with forming an interim board of directors during the month of February," said a statement by USA Gymnastics.
