Nitro is one of Wheeljack's experiments. He wanted to see the effect nitrous would have on an Autobot. He found that if you filtered NO2 into the energon, it supercharges both the vehicle and robot mode. In vehicle mode, it increases the top speed. In robot mode, it allows for faster reflexes and increased strength. So he created Nitro. Wheeljack gave him the alternate form of a souped up street racer. He dual wields full auto blasters. He's still young and cocky. Nitro loves to show off his abilities.