Terrence Davidson made wigs for the singer – who is known for her flamboyant hairpieces – from 2010, the year her platinum-selling debut album Pink Friday was released.
The wigs were a large part of the physical transformation that helped catapult her to superstardom.
In the lawsuit, Mr Davidson says he and Minaj’s representatives discussed launching a reality TV show or creating a new wig line. Nicki Minaj sells her own branded wigs on her website.
Instead, Mr Davidson said he was later ignored by Minaj who went on to sell branded wigs for massive profits on her website. He accuses her of harming his business.
In the lawsuit accessed by Time magazine, Mr Davidson’s lawyer said: “Her lawyers may complicate it, but we don’t need to get into intellectual property law. This is basic American morality. Nicki Minaj lied to this man and cheated him.”
His lawyers added that Mr Davidson created “fresh, hip and unique wigs” that “significantly contributed to Minaj’s unsurpassed notoriety for her wigs”.