Place the sliced chicken in a large bowl. Add olive oil, lime juice, chili powder, paprika, cumin, garlic powder, onion powder, oregano, salt, and black pepper.
Toss well until the chicken is evenly coated. Let it marinate for 15–30 minutes.
Heat a large skillet or cast-iron pan over medium-high heat.
Add the marinated chicken in a single layer and cook for about 5–7 minutes, turning occasionally, until browned and fully cooked.
Transfer the cooked chicken to a plate and set aside.
Add a little more oil to the same skillet if needed.
Add the sliced onion and bell peppers. Cook for 4–6 minutes, stirring occasionally, until slightly softened but still crisp.
Add the minced garlic and cook for about 30 seconds until fragrant.
Return the chicken to the skillet and toss everything together.
Cook for another 1–2 minutes so the flavors combine.
Warm the tortillas in a dry skillet or microwave until soft and flexible.
Fill each tortilla with the chicken and vegetable mixture.
Top with avocado, cheese, sour cream, salsa, and fresh cilantro.
Serve immediately with lime wedges.