Preheat your oven to 375°F (190°C).
Poach the chicken breast in simmering water for 12-15 minutes until cooked through, then shred with two forks.
Heat avocado oil in a skillet over medium heat and sauté the diced red onion and bell pepper until softened.
In a small bowl, whisk together the tomato puree, chili powder, cumin, garlic powder, and sea salt to create the red chili sauce.
Mix the shredded chicken with half of the red chili sauce and the Greek yogurt until well combined.
Warm the corn tortillas slightly in a dry pan to make them pliable.
Divide the chicken mixture between the two tortillas, roll them tightly, and place them seam-side down in a small baking dish.
Pour the remaining sauce over the top of the tortillas and sprinkle with the sharp cheddar cheese.
Bake for 15 minutes until the cheese is melted and the sauce is bubbling.
Allow to cool for 5 minutes before serving.