Preheat your oven to 375°F (190°C).
Dice the chicken breast into small bite-sized pieces and season with chili powder, cumin, sea salt, and black pepper.
Heat olive oil in a skillet over medium heat. Sauté the diced onion and red bell pepper until softened, about 4 minutes.
Add the seasoned chicken to the skillet and cook until browned and cooked through, approximately 6-8 minutes.
In a small bowl, whisk together the red enchilada sauce and Greek yogurt until a smooth, creamy sauce forms.
Cut the corn tortilla into thin strips or small squares.
In a small oven-safe baking dish, layer half of the tortilla strips, followed by the chicken and vegetable mixture.
Pour the creamy chili sauce over the chicken and top with the remaining tortilla strips.
Sprinkle the shredded sharp cheddar cheese evenly over the top.
Bake for 15-20 minutes until the cheese is melted and bubbling and the edges are slightly crisp.
Remove from the oven and let cool for 5 minutes before serving.