Preheat your oven to 375°F.
Heat avocado oil in a skillet over medium heat and sauté the diced onion and red bell pepper until softened.
In a small bowl, combine the tomato puree, ancho chili powder, garlic powder, cumin, sea salt, and black pepper to create the sauce.
In a separate bowl, mix the shredded cooked chicken breast with two tablespoons of the prepared sauce and the sautéed vegetables.
Warm the corn tortillas slightly to make them pliable, then dip each one into the sauce to lightly coat.
Place a portion of the chicken filling into each tortilla, roll them tightly, and place them seam-side down in a small baking dish.
Pour the remaining sauce over the top of the enchiladas and sprinkle with the sharp cheddar cheese.
Bake for 15 minutes until the sauce is bubbling and the cheese has melted into a golden crust.
Garnish with a dollop of Greek yogurt and fresh chopped cilantro before serving.