If you're shaking your head trying to figure out what ¡Chócalas! means, then I feel a whole lot better because I had no idea what it meant either. The good news is the translation is both simple, fun and surprisingly universal...it's not just for México.
It means.....High five!
You can actually say this a few different ways...
¡Dame esos cincos!
¡Choca esos cinco!
Technically speaking, chócalas implies that you'll high-five with both hands, while chócala only uses one. But my always helpful Spanish tutor informs me that you'll hear chócalas even if you only high-five with one hand.
Now you're well prepared to go watch a game of futbol and celebrate that goal the right way!