Korgan respected the deal because it benefited him. While he never commits anything overtly chaotic that I can remember, everything he says and how he acts suggests he's neutral. He has no respect for the law or social conventions, and live by no other creed than what benefits himself, but also have no qualms about entering a deal and sticking to it. Generally, someone that is lawful respects order and hierarchy as a social or personal good, and acts according to principles, whether personal, apersonal, or simply social. Korgan shows no such inclinations. Someone who is chaotic not only does not display any respect for law and order, nor see it as a social ormpersonal good, but also acts accordingly, often seemingly on whim, nor seek to live a structured life according to principles beyond immediate wants or needs, save for questionable personal or moral principles at best. Again, Korgan in no way actually oppose law and order, either, and don't mind taking advantage of it when it suits him, such as adhering to the principles of a contract when enforced by people more principled than himself (but he also has no issue breaking this when it suits him: the law and social convention applies to others, not to him, and he knows it).
And given that he is remarkably selfish as a singular defining trait above all others, he can't be anything other than Neutral Evil.