This story is pretty much the textbook definition of Southern Gothic. Let us count the ways:
Southern Gothic literature takes place in the first half of the twentieth century—check. All those cute archaic terms like "motor-cars" in this story give it away.
Also, Southern Gothic literature has eerie or supernatural events in the plot—check, check. Jesus is scary-eerie, and Nancy has a supernatural-like conviction that she knows Jesus is creeping around, and even sees a supernatural sign of him in the hogbone.
Finally, Southern Gothic literature explores racial issues in the American South—checkity check check check. We have the indifferent white family that only kind of cares about the terrified, helpless Nancy. We have the sadistic jailor and the even more sadistic Mr. Stovall. We have the predatory Mr. Lovelady. We have a town that is divided—white from black—by one symbolically charged ditch.