Cut the chicken into evenly sized strips or bite-sized pieces.
Mix the chili powder, cumin, paprika, garlic powder, onion powder, oregano, salt, and black pepper in a small bowl.
Toss the chicken with the olive oil and seasoning mixture until evenly coated.
Heat a large skillet over medium-high heat. Cook the chicken for approximately 8–12 minutes, turning occasionally, until browned and the thickest pieces reach 165°F (74°C).
Remove the chicken from the heat and squeeze the lime juice over it.
Warm the tortillas in a dry skillet for about 20–30 seconds per side.
Fill the tortillas with chicken, lettuce, tomatoes, cheese, avocado, red onion, and cilantro.
Finish with salsa, sour cream, or extra lime juice and serve immediately.