Preheat your oven to 400°F (200°C).
In a large mixing bowl, combine the shredded chicken, refried beans, cheddar cheese, salsa, cumin, garlic powder, onion powder, salt, and black pepper. Mix until well combined.
Lay a tortilla flat on a clean surface. Spoon about 1/3 cup of the chicken mixture onto the center of the tortilla. Fold in the sides and roll it up tightly from the bottom to the top. Repeat with the remaining tortillas and filling.
Place the rolled chimichangas seam-side down on a baking sheet lined with parchment paper. Brush the tops with olive oil to help them crisp up in the oven.
Bake in the preheated oven for 20-25 minutes, or until the chimichangas are golden brown and crispy.
Remove from the oven and let cool for a few minutes. Serve with sour cream and garnish with fresh cilantro.