Preheat your oven to 375°F (190°C).
In a small skillet, heat the avocado oil over medium heat and sauté the diced red onion and bell pepper until softened and slightly caramelized.
In a small bowl, whisk together the tomato puree, chicken bone broth, ancho chili powder, cumin, garlic powder, sea salt, and black pepper to create the sauce.
Combine the shredded chicken breast with the sautéed vegetables and 2 tablespoons of the prepared ancho sauce.
Warm the corn tortillas in a dry pan or microwave for 10 seconds until pliable.
Dip each tortilla into the sauce to coat, then fill with the chicken 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 Monterey Jack cheese.
Bake for 15-20 minutes until the sauce is bubbling and the cheese is melted and golden.
Garnish with fresh chopped cilantro before serving.