Preheat your oven to 375°F (190°C).
In a large mixing bowl, combine the shredded chicken, cooked rice, black beans, corn, salsa, cumin, chili powder, garlic powder, and onion powder. Mix well until all ingredients are evenly incorporated.
Lay out a flour tortilla on a clean surface. Spoon about ½ cup of the chicken mixture onto the center of the tortilla. Sprinkle with a little cheese, then fold in the sides and roll it up tightly. Repeat with the remaining tortillas and filling.
Place the rolled burritos seam-side down in a greased 9x13 inch baking dish.
Pour the enchilada sauce evenly over the burritos, then sprinkle the remaining cheese on top.
Cover the baking dish with aluminum foil and bake in the preheated oven for 20 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Let the burritos cool for a few minutes before serving. Top with sour cream and garnish with fresh cilantro if desired.