A slang expression with several meanings. Usually isn't a compliment, when you tell someone they're good it usually means they're doing something wrong and should stop. You would think it would be the opposite, hearing it, but it's a sarcastic expression.
It can be said like "you're good", the "chur" is just a colquialism.
To be safe, usually assume it means, "you're wrong". Used a lot in the DC area.
"Dude, we're so gonna crush your team next game"
"Chur good!"
"I look so fly in these white reeboks"
"Chur good!"