Maybe it's just me, but I always saw Moorcockian "chaos" as being more of an elemental force, a corruption of the multiverse (though from within, rather than without as in Gloranthan chaos), whereas DnD "chaos" was more of a personality thing, a pattern of behaviour. I don't know what the original DnD take was, but from my RC it's definitely a personality thing. "Gods of chaos" may have a place in the world, but chaos as a force certainly doesn't.
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Edit:
There's also the Balance to consider. In Moorcock, the Balance is also an active force (which the EC is a servant of), and even makes an appearance at the end of one of the stories (can't remember which though). DnD "neutrality" - in my RC - mentions something similar in the first para, but then goes on to describe a "sitting on the fence" personality type.
So maybe Moorcockian law/chaos may have provided the idea, but the implementation sure seems different...