Nitrogen will make no measurable difference. Air is about 80% nitrogen already. The properties of nitrogen vs. air are very similar for normal situations. Racing cars use nitrogen to get a slightly more uniform pressure at the very high temperatures experienced at high speed but street cars don't see those temperatures.

One advantage is less deterioration from moisture and oxidation, but the tire manufacturers say that this is unnecessary for tires under normal service. Nitrogen is used in airplane tires that may be in use for many, many years and see extreme temperature differences.

Another supposed advantage is that nitrogen loses pressure slower. Consumers Report tested this and found it was true. But the nitrogen tires lost only about 1 less PSI per year. Hardly a big deal.