Preheat your oven to 375°F (190°C) and lightly grease a small baking dish.
In a small skillet over medium heat, add the olive oil and sauté the diced yellow onion and minced garlic until translucent and fragrant.
In a mixing bowl, combine the cooked shredded chicken breast with the sautéed aromatics, ground cumin, garlic powder, onion powder, sea salt, and black pepper.
Stir 2 tablespoons of the tomato puree and half of the ancho chili powder into the chicken mixture to ensure the filling remains moist during baking.
Warm the corn tortillas slightly in a dry pan or microwave to make them pliable, then divide the chicken filling evenly between them.
Roll the tortillas tightly and place them seam-side down in the prepared baking dish.
Whisk the remaining tomato puree and ancho chili powder together in a small bowl, then pour the sauce evenly over the rolled tortillas.
Sprinkle the shredded sharp cheddar cheese over the top and bake for 15-20 minutes until the sauce is bubbly and the cheese is melted.
Garnish with fresh chopped cilantro before serving.