I have never seen a Nissan/Infiniti use anything BUT NGK...for decades. Maybe the brand new cars are different, but I have Nissan knowledge going back to the model year 1997 (my first Maxima) and I've had 3 cars (99 Maxima, 07 M35x and now my 11 M56x) and all of them are NGK.
EDIT: I did some digging and turns out the M37/Q70 3.7 uses Denso while the M56/Q70 5.6 uses NGK. Color me edumacated
. Did not hear or know that Nissan started using anything other that NGK.
Here is a screen shot. Page 3/4 of the FWD section of the 2011 Infiniti M Factory Service Manual.