I regularly run an 18 gauge nail gun off of my small refillable nitro cylinder. Works well, I get at least 30+ nails from a tank. No idea how long a 40 would drive a framing nailer.
Sure you can. NASCAR has been using nitro tanks to do tire changes for years. It's actually better for the tools because there's no moisture in it.
use co2 instead, the tank will last longer, don't forget to oil your gun
CO2 and N2 would work. Just depends on size of gun and tank as to how long. I have aired up tires with my N2 tank. Paslode Cordless Frame guns are cool too. Just EXPENSIVE!