Revell has been HQ'ed there for a long time...I'd assume it's manufactured in China, as the tire bag photo shows.
Edit: That is odd--
it says 'Packaged in USA', 'Plastic Parts Molded in USA', 'Tires Molded in China'. What's up with that? Revell has US manufacturing/molding capability? Thought that had long ago been offshored....
Checked a few other recent Revell kits in my closet--the new '57 Chevy Bel Air convertible and S&M Cuda simply say made in China, while the old tool '57 Chevy ht (Roth kit) has similar notes to the Datsun..