The correct OEM plugs are double platinum:
[COLOR=#0072BC ! important][COLOR=#0072BC ! important]NGK[/COLOR][/COLOR] PFR6B-9
And I think this is the Nissan Part Number:
22401-27N66

You can also use NGK Iridium:
BKR6EIX
BKR6EVX
BKR6EIX-P

Or traditional spark plugs:
BKR6E - Price (AutoZone) $2.09
BKR7E

You can change all those sixs to sevens to get colder plugs.
(e.g. BKR7EIX)