I might could say something about snobby grammarians...bless their hearts...but I won't.

As a well educated native of southern Appalachia (BA in English; PhD in Education), I can say with confidence that might could is mighty useful modal construction that conveys nuance and a sophisticated appreciation of the historical English, at least as spoken by the Scotch Irish settlers who populated these parts.
https://en.wikipedia.org/wiki/Appalachian_English