In a real nitrous system for four stroke auto(full sized for whatever) along with the nitrous (Ice cold air charge ie very dense, that's all that nitrous is)you're injecting a huge amount of extra fuel to keep the mixture at the correct ratio, because without the extra fuel you'll go very lean and make no power, ie burn up. You're still pushing it past the limits most of the time, that's why putting nitrous on our Civic is kewl to watch, but it won't last long without some serious reinforcing of engine components.
Also, a water/alcohol injection system is common on a nitrous engine to help battle detonation(ping) because of the high compression of all that extra cold air/fuel charge in the cylinder head.

Our little model engines are very inefficient, they're high loss poor fuel managers, and even worse, they're maxed out already because head pressures are high and we use fuel that's has nitro in it. By adding nitrous(Ice cold very dense air ) with no extra fuel it'll go lean and cook in short order. But by adding fuel to make the mixture right....kiss the head good bye because it'll go flying, unless you can keep all that inside the engine(Good luck!).

Forced air(Turbo or supercharged):
The way a two stroke engine functions is detrimental to forced air induction without modifying the port timing drastically to try to keep the fuel/air charge inside, we rely on our tuned exhaust systems to do that for us, in fact our engines are supercharged already, but we use the tuned pipe to do it, it effectually sucks the mixture into the head, then helps pack it in tightly at the right time(Just before ignition.). See this animation on how it works.


Now, you can see that if you try to force air into the head mechanically that you'll actually push all the good stuff(the supercharged air/fuel mix) right on through the engine and it'll never burn because it'll be out of the cylinder.

I'm sure I'll be corrected on several points, but that's the general deal with nitrous, turbocharged or mechanical superchargers on our model engines the way I see it.

I had to edit it to seperate the two(Nos and forced air) I wasn't fully awake I guess.