+1 to all here that post the fact the reason for nitrogen inflation is due to the fact it is water free. That keeps the pressure more stable. Also since air from your pump is 78% nitrogen you are naturally almost 80% on your way to having nitrogen inflated tires.

But really guys worrying about this is kinda like an knats hind leg sand papered on both sides. Arguing over this make the weight weenies look like rocket scientist.