Preheat your oven to 375°F (190°C).
Heat the olive oil in a small skillet over medium heat; sauté the diced onion and red bell pepper until they are soft and translucent.
In a mixing bowl, combine the cooked shredded chicken with the sautéed vegetables, cumin, garlic powder, sea salt, and black pepper.
In a separate bowl, whisk together the tomato puree and chili powder to create a simple, clean red chili sauce.
Spread a thin layer of the sauce on the bottom of a small baking dish.
Warm the corn tortillas slightly to prevent cracking, then dip each one into the sauce to coat.
Fill each tortilla with the chicken mixture, roll them tightly, and place them seam-side down in the baking dish.
Pour the remaining sauce over the top of the tortillas and sprinkle evenly with the shredded cheddar cheese.
Bake for 15 minutes until the cheese is melted and the sauce is bubbling.
Garnish with freshly chopped cilantro before serving.