"That's chickin" is a slang phrase used to express approval for something that is neither chill nor kickin' but somewhere in between. "Chickin" lies smack in the middle of that spectrum. It's a lukewarm phrase never to be followed with an exclamation point or too much enthusiasm in the voice.

When some little bitchboy is acting like a little tiny pee pee poo poo baby and messing up the group plans.