What kind of headers fit Chevy motor to Nissan truck?

You can't directly bolt Chevy engine headers onto a Nissan truck. Chevy and Nissan engines have completely different bolt patterns, head configurations, and exhaust port locations. You'd need custom headers or headers specifically designed for a Chevy engine swapped into a Nissan truck. These are not readily available off-the-shelf and would likely need to be fabricated.