Preheat your oven to 375°F and lightly grease a small oven-safe baking dish.
In a small skillet over medium heat, sauté the diced white onion and bell pepper in olive oil until they are softened and slightly caramelized.
In a medium mixing bowl, combine the cooked shredded chicken with the sautéed vegetables and half of the chili powder, cumin, garlic powder, and onion powder.
In a separate small bowl, whisk together the tomato puree, remaining spices, sea salt, and black pepper to create a smooth red chili sauce.
Warm the corn tortillas briefly in a dry pan or microwave for 10 seconds to make them pliable and prevent cracking.
Spread a thin layer of the sauce on the bottom of the baking dish, then dip each tortilla into the sauce, fill with the chicken mixture, roll tightly, and place seam-side down in the dish.
Pour the remaining red chili sauce over the top of the rolled tortillas, sprinkle with the shredded sharp cheddar cheese, and bake for 15 to 20 minutes until the cheese is bubbly and golden.