Adjust oven rack to middle position and turn on broiler. Heat oil in a large (12 inch) skillet over medium-high heat. Add 2 tablespoons of the chili powder, beans, corn, chiles, salsa, and 1/4 cup of the cilantro; simmer to blend flavors, about 5 minutes.
Meanwhile, bring 3 cups of water, cornmeal, remaining 2 teaspoons of chili powder, and 1 teaspoon of salt to boil in a large saucepan or Dutch oven, whisking frequently until mixture thickens to soft mush consistency, just a couple of minutes. (If not topping it with cheese, stir in plant-based butter now.)
Pour mush over hot bean mixture, spreading with a spatula to completely cover. Sprinkle with optional cheese, remaining 1/4 cup of cilantro, and the crumbled chips. Broil until chips turn golden brown, cheese, (if using) melts, and mush gets a little crusty, about 5 minutes. Let rest for 5 minutes and serve.