Preheat your oven to 375°F (190°C).
Heat the avocado oil in a small skillet over medium heat and sauté the diced onion and bell pepper until soft and translucent.
In a small bowl, whisk together the tomato puree, chili powder, ground cumin, garlic powder, sea salt, and black pepper to create the red chili sauce.
In a separate bowl, combine the shredded chicken breast with the sautéed onions and peppers.
Warm the corn tortillas slightly in the microwave or on a dry pan to make them pliable.
Dip each tortilla into the red chili sauce to coat lightly, then fill with the chicken and vegetable mixture and roll tightly.
Place the rolled tortillas seam-side down in a small baking dish, pour the remaining sauce over the top, and sprinkle with the shredded cheddar cheese.
Bake for 15 minutes or until the sauce is bubbling and the cheese is golden and melted.