Rapper has also reportedly not paid rent on his flat for almost a year
Nas reportedly owes over $6.4million (£4million) in unpaid taxes.
The Internal Revenue Service (IRS) filed a legal challenge on January 10 over an unpaid tax bill of $514,000 (£322,000), which added to claims for $3million (£1.9million) filed in February 2010, and $2.5million (£1.6million) in October 2009, bringing Nas‘ alleged IRS debt to $6.4million.
Rolling Stone magazine reports that the rapper has also not paid the rent on his flat for almost a year.
The rapper has not commented on the reports, but is expected to have to report to court over the challenges at some point in 2011.