Preheat the oven to 350°F. Spray an 8x8-inch casserole dish with non-stick cooking spray; set aside.

Combine water and salt in a large saucepan. Bring to a boil, then reduce to low heat.

Whisk in the corn meal. Cover and simmer for 15 minutes, whisking every 5 minutes to remove any clumps, until polenta is thickened and pulls cleanly away from the side of the pan.

Remove from heat and stir in butter and 1/4 cup cheddar cheese. Cover and let the mixture stand for 5 minutes, until the cheese is melted.

Spread the hot polenta into the prepared baking dish. Bake in the preheated oven for 20 minutes. (If your chili has been refrigerated, use this time to reheat it in a small saucepan on the stove or in the microwave.)

Layer the corn kernels, chili, and the remaining 1 3/4 cups of cheese over the top of the polenta.

Return to the oven and bake for an additional 15 minutes, until the casserole is heated through and the cheese is melted.

Sprinkle with scallions and serve hot.