Preheat your oven to 375°F and lightly grease a small baking dish with a drop of avocado oil.
In a skillet over medium heat, sauté the diced onion and red bell pepper in avocado oil until they become soft and fragrant.
Stir in the shredded chicken breast, cumin, garlic powder, sea salt, and black pepper until the mixture is well combined and heated through.
In a small saucepan, whisk together the tomato puree, chicken bone broth, and ancho chili powder, simmering for 5 minutes to create a thick sauce.
Lightly warm the corn tortillas, then dip each one into the ancho sauce to coat both sides.
Place a portion of the chicken and pepper mixture into each tortilla, roll them tightly, and place them seam-side down in the baking dish.
Pour the remaining ancho sauce over the top of the tortillas and sprinkle evenly with the sharp cheddar cheese.
Bake for 15 minutes until the cheese is melted and the sauce is bubbling, then garnish with fresh cilantro before serving.