He was arrested in Dubai in June, and extradited to the United States of America, appeared in court last Thursday.
He was charged with running a global fraud operation, including targeting a Premier League football club, a bank and a US law firm.
Ramon Olorunwa Abbas, 37, who claims to run a real estate business, is alleged to have conspired to launder hundreds of millions of dollars through business email compromise (BEC) frauds and other scams, the US Department of Justice (DoJ) said.
He is also accused of laundering $14.7m stolen in a cyber-heist from an unnamed bank in February 2019, sending the money to bank accounts around the world.
FBI special agents obtained custody of Abbas and took him to Chicago.