Can I run Nitro For a while, then beer gun later?

I'm assuming this would work fine, but thought I would run it by everyone in case someone could confirm it for me. My Plan is to carbonate the beer at low levels, then serve it on my Nitro Tap handle for a month or so. Then take what is left over, purge the keg with CO2, raise the carbonation up to normal levels, then bottle with beer gun. Anyone see any cause for concern with this plan? Since the Nitrogen never actually gets in the beer I'm assuming it should work fine.
Thanks
Brad

Forget to add that I'm serving with Pure Nitrogen, not beer gas.