Prepare Oven and Pan: Set your oven to preheat at 415∘F (213∘C).
Lightly grease a large baking sheet with oil or use nonstick cooking spray.
Combine Spices: In a small bowl, mix together the chili powder, cumin, oregano, smoked paprika, optional cayenne pepper, salt, and black pepper. Set aside.
Arrange Ingredients: Distribute the sliced chicken strips, bell pepper strips, onion wedges, and minced garlic evenly across the prepared baking sheet. Try to keep them in a single layer for even cooking.
Season and Coat: Drizzle the olive oil over the chicken and vegetables on the baking sheet. Sprinkle the prepared spice blend evenly over everything. Use tongs or your hands to gently toss the ingredients until they are well-coated with oil and spices.
Bake: Place the baking sheet into the preheated oven. Bake for 28-33 minutes. Check if the chicken is fully cooked (no longer pink inside) and the vegetables have reached a tender-crisp consistency. Cooking time may vary slightly depending on your oven and the thickness of the chicken/vegetables.
Finish with Lime: Once cooked, remove the baking sheet from the oven. Drizzle the fresh lime juice over the hot chicken and vegetables and toss gently to combine.
Serve: Serve the baked chicken and peppers immediately. Offer warmed low-carb tortillas and optional sliced avocado on the side if desired.