Preheat your oven to 375°F.
Season the chicken breast with half of the sea salt and black pepper, cook until the internal temperature reaches 165°F, then shred finely with two forks.
In a small skillet, heat the olive oil over medium heat and sauté the chopped onion and minced garlic until soft and translucent.
Stir in the ancho chili powder, cumin, tomato puree, and chicken broth; simmer the mixture for 5 minutes until the sauce thickens slightly.
Lightly warm the corn tortillas in a dry pan or microwave for 10 seconds to make them pliable.
Dip each tortilla into the sauce to coat, fill with the shredded chicken, roll tightly, and place seam-side down in a small baking dish.
Pour the remaining ancho sauce over the top of the rolled tortillas and sprinkle with the shredded cheddar cheese.
Bake for 10 to 12 minutes until the cheese is melted and the sauce is bubbling.
Serve immediately topped with a dollop of Greek yogurt and a sprinkle of fresh cilantro.