If you install it RIGHT, nitrous can be very safe. Engine wear is no higher with a properly installed nitrous system than it would be for a supercharger or turbo producing the same increase in power. If anything, it might even be easier on your engine, considering the cooling effect that it produces and that it is not always operating.
A 75 shot is pretty mild, so do your homework and install all the supporting mods, and I imagine you'll enjoy a reliable performance increase.