Green’s Dictionary of Slang

1. a phr. implying that nothing new has happened, there is no information to pass on; usu. as response to the query what’s happening?

1968		‘Hy Lit’ Hy Lit’s Unbelievable Dict. of Hip Words 46: you got it – true acknowledgement that you have mastered the entire situation.
1972		D. Claerbaut Black Jargon in White America 87: you got it a statement usually in response to the greeting – What’s happening? – and often meaning that nothing is really happening that the other person does not understand: What’s happening, man? You got it.

2. (orig. US esp. black) a general affirmative reply, usu. to a yes/no question.

1975		G. Underwood ‘Razorback Sl.’ in AS L:1/2 69: you got it An affirmative response, usually said in response to a yes-no question (black use).
1978		R. De Christoforo Grease 194: ‘Right.’ ‘You got it!’ ‘Friggin’ A!’.
1986		T. Philbin Under Cover 23: ‘I hate it [...] but I understand. We’re cops, right?’ ‘You got it.’.
1998		(con. 1960s) G. Washington Blood Brothers 13: ‘You got it lady,’ I said.
2000		M. Collins Keepers of Truth 264: Sure, Ronny. You got it.