Preheat oven to 375°F (190°C).
Poach or grill the chicken breast until cooked through, then shred with two forks.
In a small skillet, heat olive oil over medium heat and sauté diced red onion and bell pepper until softened.
In a small bowl, whisk together tomato puree, chili powder, cumin, garlic powder, sea salt, and black pepper to create the red chili sauce.
Toss the shredded chicken with half of the red chili sauce and the sautéed vegetables.
Warm the corn tortillas slightly to prevent cracking, then fill each with the chicken mixture and roll tightly.
Place the rolled tortillas seam-side down in a small baking dish, top with the remaining sauce and shredded cheddar cheese.
Bake for 15 minutes until the cheese is melted and bubbly, then garnish with fresh cilantro before serving.