Like Skull Bash and the like. Also, what is the chance that it will raise Speed?
I checked online, Nitro Charge doesn't require charging, despite the name. And from the looks of it, Nitro Charge raises your speed every time you use it. but the guy playing could have been REALLY lucky. But I'm guessing it boosts every time you use it, because it seems too unlikely for it to boost that many times on probability.