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 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 the sides of the tortilla over the filling, then roll it up tightly from the bottom to the top, creating a burrito shape. 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 lightly with olive oil.
Bake in the preheated oven for 20-25 minutes, or until golden brown and crispy.
Remove from the oven and let cool for a few minutes before serving. Garnish with sour cream and chopped cilantro.