Preheat your oven to 375°F (190°C).
In a large oven-safe skillet, heat the olive oil over medium-high heat. Add the sliced chicken and cook for about 5-7 minutes, stirring occasionally, until the chicken is browned and cooked through.
Add the sliced bell peppers and onion to the skillet. Sprinkle with chili powder, cumin, garlic powder, onion powder, salt, and pepper. Cook for an additional 5 minutes, stirring occasionally, until the vegetables are tender.
Remove the skillet from heat and layer the tortillas over the chicken and vegetable mixture, overlapping them slightly.
Pour the salsa evenly over the tortillas, then sprinkle the shredded cheddar cheese on top.
Transfer the skillet to the preheated oven and bake for 15-20 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it cool for a few minutes. Garnish with fresh cilantro if desired, then slice and serve.