Are NASCAR tires Staggered

Answer 1

Not any more.

"Stagger" is a technique used to make race cars with bias ply tires more stable. You put either bigger tires or higher tire pressure on the right side. Sprint cars and other series where they're not trying to "make everyone equal" use bigger tires; because NASCAR has always mounted the tires for you they put more air in the rights.

This has naturally led to some of the more vicious wrecks in the history of the sport - if you are running five pounds of stagger and accidentally put a right-side tire on your left front, you go straight into the wall at full racing speed.

They don't use stagger with radial tires because it doesn't do anything for you.