Chingón is another one of those words that is very Mexican. The word itself may not be unique to Mexico, but it's definition and usage in this context is very Mexican.
Ser chingón means to good at something. In fact, not just good, but really fucking good. As always, exact translations with words like this are hard to come by, but in English it might translate to something like:
Bad-ass, kick-ass, the shit, really fucking good, pretty damn good, etc, etc.
And as usual, context is key to translation. Let's look at some examples:
Mi amigo es chingón para el futbol
My friend really fucking good at soccer
Tu carro está chingón
Your car is the shit
¿Viste esos zapotos? ¡Son chingones!
Did you see those shoes? They're kick-ass!
Tú cabrón pero yo chingón
You're damn good, but I'm fucking better
I'm guessing you already know how to translate our expression at this point:
Soy más chingón que tú
You're good, but I'm fucking better
Now, if you're on the receiving end of the above comment, don't worry, I've saved the best for last.
If someone absolutely insists that they're más chingón que tú, simply tell them...
Eres chingón, pero yo soy el chingón de chingones
You're fucking good, but I'm the fucking best of the best
I want to leave you all with one final example. This picture gave me a chuckle, so I thought I'd share it with you.