Preheat your oven to 375°F (190°C).
In a large bowl, combine the shredded chicken, cooked rice, black beans, corn, salsa, cumin, chili powder, garlic powder, onion powder, salt, and pepper. Mix well until all ingredients are evenly incorporated.
Lay out a tortilla on a clean surface. Spoon about 1/2 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 any remaining salsa over the top of the burritos, then spread the sour cream evenly over the salsa.
Sprinkle the remaining cheese on top of the burritos.
Cover the baking dish with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let cool for a few minutes. Garnish with chopped cilantro if desired before serving.