Nitrous is a race only application so it doesn't fit what you just said - having said that, it is a cheap power adder at the track. (nitrouS not nitro, nitro is slang for "nitro methane" a completely different thing). Also nitrous itself is not flammable and no more likely to "blow up" than your radiator - despite the "Fast and Furious" crowd and screaming "nnaaawwwwzzzzz" and having cars blow up.
As far as your mileage and supercharging the car, go for it. I put the Xcharger on my car at 90,000 miles, after two race seasons with a 75 shot of nitrous. I now have 198,800 on the car, still stock top and bottom ends of the engine.