As you probably already know, P0430 is a catalyst efficiency code for bank 2, which is the driver's side. If you are saying the code re-triggers as soon as you clear it without even starting the vehicle, that is not a common problem and usually indicates an current electrical circuit "short" or "open." Normally, after erasing the code, it takes a little bit of driving for the P0430 to trigger, which is most often caused by an inefficient, upstream converter on that bank or an exhaust system leak; cracked or broken manifold flanges aren't unheard of on the VQ40DE. You could always follow the P0430 diagnostics listed in the Engine Control section of the 2006 Pathfinder factory service manual, which you can find here:
Nissan Service Manuals - NICOclub