Well maybe I am too foreign, but to me he could of just said he is sorry, but instead of that he said not really with comma, I am sorry. Anyhow, the nick means more or less cat pissed (pants or place etc), in our language it's sort of one word for pissed in not specified place. Either way nick isn't the best, ain't arguing about.
If you are sorry, that's fine, but do it again, no chance of coming back. No need for immature people like that here.