I think in such a situation where the criminals press charges. That chuck would probably win the case. After all, it was chuck defending himself at knife point.
Perhaps a jury would think that chuck went too far with the ass whooping? I can see that happening. He was pretty damn brutal to the knife bearers. But, we don't know exactly how the ass whooping occured. All we know is how it started and how it ended. We have no idea if it was necessary for chuck to break all their arms in the fashion that he did, or if he could have eventually knocked them out; because we have no idea how much the knife bearers sucked at knife fighting. One big detail i do suspect however is that chuck kicked their asses in a way that says "look at how brutally i disabled all of you from using a knife, i could have just scrotum-ball-ripped your dicks off instead you dumb ****ers".
In the end, chuck was in the right. I don't think he'd have to worry too much about the criminals pressing charges except in the area of thinking perhaps chuck was too extreme. Other than that, i think chuck would still win the case.