Preheat your oven to 375°F (190°C).
Sauté the diced red onion and bell pepper in olive oil over medium heat until softened and fragrant.
In a medium bowl, combine the shredded chicken breast with the sautéed vegetables, sea salt, black pepper, and garlic powder.
In a separate small bowl, whisk together the Greek yogurt, tomato puree, and minced chipotle peppers until the sauce is smooth and creamy.
Spread two tablespoons of the chipotle sauce across the bottom of a small baking dish to prevent sticking.
Warm the corn tortillas slightly to make them pliable, then dip each one into the sauce before filling with the chicken mixture and rolling tightly.
Place the tortillas seam-side down in the baking dish, top with the remaining sauce, and sprinkle with shredded Monterey Jack cheese.
Bake for 15 minutes until the cheese is melted and the sauce is bubbling.
Remove from the oven and garnish with fresh cilantro before serving.