If the tire has 100% nitrogen, then a small amount of oxygen will diffuse into the tire, as @CapriRacer said. More than offset by the nitrogen diffusing out, and very very small. But it will happen.
If the tire has 100% nitrogen, then a small amount of oxygen will diffuse into the tire, as @CapriRacer said. More than offset by the nitrogen diffusing out, and very very small. But it will happen.