So it's your first bike... I understand your emotional attachment to it and not wanting to trade it in. If I were you I'd find a way to keep it... I bet there's not one person on this board that doesn't wish they still had their first motorcycle. Me? '64 Honda 305 Dream. I've been looking at them on Ebay lately.
If you really want to hot-rod your 600, have you thought about putting a turbo kit on it? More practical than nitrous, don't have to fill a tank or hit a switch. About the same $$$ for used.
I know you're excited about the NO2 and wanted encouragement, but us old farts are only going to rain on your parade with our fuddy-duddy common sense. Actually, A B1200 wouldn't be much more insurance-wise than your 600, they're both "standard" motorcycles... but if you are young, then you're gonna get hammered on just about any bike insurance.