Preheat your oven to 375°F and lightly grease a small baking dish.
Heat the olive oil in a skillet over medium heat and sauté the diced onion and bell pepper until they are softened and fragrant.
Cook the chicken breast in a separate pan until the internal temperature reaches 165°F, then shred it thoroughly using two forks.
In a small mixing bowl, whisk together the tomato puree, Greek yogurt, chili powder, ground cumin, garlic powder, and sea salt to create the zesty sauce.
In a large bowl, combine the shredded chicken and sautéed vegetables with exactly half of the prepared sauce.
Warm the corn tortillas slightly in the microwave or on a dry skillet to make them pliable.
Fill each tortilla with the chicken and vegetable mixture, roll them up tightly, and place them seam-side down in the baking dish.
Spread the remaining sauce over the top of the tortillas and sprinkle evenly with the shredded cheddar cheese.
Bake for 15 minutes until the cheese is melted and bubbling and the edges of the tortillas are slightly crisp.