Nitrogen is delivered as a dry clean gas. Air from a compressor is saturated with moisture and this moisture will change the pressures in the tire depending on the temperatures it sees. Just remember the air your putting in from a normal air compressor is putting 78% nitrogen to begin with but its also has moisture in it
air here in the desert is so dry and low in humidity that when I open the valve in the bottom to let any water out of my compressor it doesnt even make a wet spot,
no way there is enough water to make me worry enough to run out and do the nitrogen thing
Also since for all practical purposes water doesn't compress I don't see how it can contribute much if anything to changes in tire pressure
lesson learned in high school chemistry when my friend Dave Helm filled a flask all the way to the top with water and then slammed the stopper in with his fist causing the beaker to explode - - Chemistry teacher smiled and simply said "and now you have learned that water doesnt compress Mr Helm"
laughed so hard I dang near fell off my stool