Preheat your oven to 375°F (190°C).
In a medium skillet, heat the olive oil over medium heat and sauté the diced onion and red bell pepper until they are softened and fragrant.
Add the shredded chicken breast to the skillet along with the chili powder, cumin, sea salt, and black pepper, stirring for 2 minutes to combine the flavors.
Warm the corn tortillas in a dry pan or microwave for 15 seconds to make them pliable and prevent them from tearing.
Spread a small amount of enchilada sauce on the bottom of a small baking dish.
Place a portion of the chicken mixture into each tortilla, roll them up tightly, and place them seam-side down in the baking dish.
Pour the remaining enchilada sauce over the top of the tortillas and sprinkle evenly with the shredded cheddar cheese.
Bake for 15 minutes until the sauce is bubbling and the cheese has completely melted.
Remove from the oven and top with a dollop of Greek yogurt and a sprinkle of fresh cilantro before serving.