Mr Nadel went missing for two weeks when the Securities and Exchange Commission initially charged him with fraud in January.
He later turned himself in to police in Florida. The fund manager is currently in prison in New York because he has not been able to meet the conditions set for his $5 million bail, Reuters reports.
According to charges filed with the US district court in Manhattan, around 350 investors pumped money into funds for which Mr Nadel was the principal investment adviser. Prosecutors say he provided misleading information regarding the funds' historical returns and assets while at the same time taking millions of dollars in fees.
Mr Nadel's lawyer Mark Gombiner said the hedge fund manager intends to plead not guilty to all 15 counts.
If convicted, the 76-year-old faces the prospect of spending the rest of his life in prison as each count carries a maximum sentence of up to 20 years.