Nas -- The Tax Man Cometh ... For Rapper's Concert Cash

The State of Georgia is rooting for Nas to make a fortune on his concert tour ... because the government just got the green light to garnish a MILLION BUCKS from his earnings to repay a massive tax debt ... TMZ has learned.

The Georgia Department of Revenue has filed new legal docs in their effort to collect $1,083,435 from the rapper for taxes it claims Nas owes for the years 2006, 2007, 2009, 2010.

According to court docs, the GDR obtained an order commanding Live Nation -- the promo company behind Nas' tour with Lauryn Hill -- to garnish his wages until the dept is satisfied.

The tour is currently underway, and Nas -- who's also on the hook for millions in unpaid taxes to the federal government -- is sure to make a boatload of money.

A rep for Nas tells us the matter has recently been settled -- but the GDR insists the case is still open and they're trying to collect.