Documents filed with New Zealand courts by the US stated Nomm would testify that Megaupload's content auditing team in the Philippines was "not very effective and that many of the auditors did not even know what copyright was".
Nomm said he often handled technical problems raised by users who had trouble viewing files and when he checked found many contained the "FBI Anti-Piracy" label.
The court document stated: "Nomm specifically advised Dotcom and (co-defendant Mathias) Ortmann about the legality of the files being hosted. At some point after he was hired, Nomm realised the group's reliance on and benefits from illegal copyright infringement and yet he continued to work with them. He believed they were likely to be sued civilly at some point."
Nomm also told the FBI he was "surprised" to find out how much those he was testifying against were making - Dotcom pulled in US$42 million in 2010 - and that he was required to work between 10 and 12 hours a day, seven days a week.
Dotcom has previously said Nomm had decided to make the deal after years of unemployed isolation in the Netherlands, away from his son in Turkey. "I can understand why Andrus did it. But it doesn't change the fact that he is innocent."
Meanwhile, a Dotcom documentary is in the works backed by $820,000 of taxpayer money made available through the NZ Film Commission.
With a working title Caught in the Web, the film is being made by award-winning documentary makers Professor Annie Goldson and Alex Behse. Professor Goldson said work on the documentary had been under way for several years and it was aimed for release next year.
"When the police raided the Kim Dotcom mansion, it created a media firestorm around the world sparking another battle in what are often called the 'copyright wars'. New Zealand has found itself caught in the crossfire in what is a highly polarised debate."
She said the document explored "how we consume entertainment and information, privacy and surveillance, sovereignty and New Zealand's relationship to the US".