1. Preheat the oven to 425°F and line a baking sheet with parchment paper.

2. Heat 1 tablespoon of olive oil in a skillet over medium heat and cook the chopped onion until softened, about 3 to 4 minutes.

3. Stir in the minced garlic and cook for 30 seconds until fragrant.

4. Add the shredded chicken, taco seasoning, salsa, and cream cheese, then stir until the filling is hot and creamy.

5. Remove the skillet from the heat and mix in the cheddar cheese and Monterey Jack cheese.

6. Warm the flour tortillas for a few seconds so they are soft and easy to fold.

7. Divide the chicken filling evenly among the tortillas, placing it in the center of each one.

8. Fold in the sides, roll each tortilla tightly like a burrito, and place seam side down on the prepared baking sheet.

9. Brush the tops and sides with the remaining olive oil or melted butter.

10. Bake for 18 to 22 minutes, or until the chimichangas are crisp and golden brown.

11. Serve hot with sour cream, pico de gallo, chopped cilantro, and fresh lime wedges.