Nitro is simply something that we use in model engines for a bit more power and smoother running. Drag racers use a lot of it for a lot of power.

The term 'nitro' is actually an old term back in the early racing days. It's been around for 50 years or so. You have nitro fuel for models and body building. Nitro for hearts. Nitro wrestling. Nitro drag racing. Nitro engines. Just a part of the language and engine lore.