Since the buckle was not used but the pretensioners were activated, you must replace the pretensioners but should have all hardware (including buckle) inspected to make sure there's no concerns.
If you and the passenger were belted and the accident was severe enough, you'll definitely want to replace EVERY part including the bolts, height adjuster, buckle, etc.
From the owner's manual:
All seat belt assemblies, including retractors and attaching hardware, should be inspected after any collision by a NISSAN dealer. NISSAN recommends that all seat belt assemblies in use during a collision be replaced unless the collision was minor and the belts show no damage and continue to operate properly. Seat belt assemblies not in use during a collision should also be inspected and replaced if either damage or improper operation is noted.
The pretensioners cannot be reused after activation. They must be replaced together with the retractor
and buckle as a unit.
2008 Rogue for reference, in case you're curious on the part breakdown:
The pretensioner, retractor and webbing comes as a complete assembly. Hardware including mounting, height adjuster and buckle are separate pieces.
Are the repairs going to be done at a collision center or dealer and is this covered by insurance?
If so, they should take care of it.