Most auto technicians that specialize in Asian makes will tell you the best plug is the original equipment plug, which is almost always NGK or Denso. Many have found misfire issues with Bosch platinums used in Nissans and I once saw a hole burnt in the side of an old E16S Sentra engine piston where the owner used Champions. I worked for Nissan for 16 years and the only spark plug I use in any gas engine I own is NGK, be it a Nissan Pathfinder or my Husqvarna chain saw! For the original equipment plug and gap setting for any application, you can go to:
www.NGKSparkPlugs.com
Also, platinum and iridium spark plug gap should be checked and, if needed, adjusted prior to installing, but they should never be adjusted after they have been run.