In a large mixing bowl, combine the sliced chicken breast with 2 tbsp olive oil, lime juice, chili powder, ground cumin, smoked paprika, garlic powder, onion powder, dried oregano, 1 tsp salt, and 1/2 tsp black pepper. Toss well to ensure all chicken strips are evenly coated. Let it marinate at room temperature for at least 15 minutes, or refrigerate for up to 30 minutes for a deeper flavor.

While the chicken marinates, slice all bell peppers (red, green, yellow) and the large onion into thin, uniform strips. This ensures even cooking.

Heat 1 tbsp of olive oil in a large cast-iron skillet (or any heavy-bottomed pan) over medium-high heat until it shimmers and is very hot. This high heat is crucial for a good sear.

Add the sliced onions and bell peppers to the hot skillet. Sauté for 5-7 minutes, stirring occasionally, until they are tender-crisp and slightly charred. Avoid overcooking them; they should still have a bite. Remove the cooked vegetables from the skillet and set them aside on a plate.

Increase the heat to high. Add the marinated chicken strips to the same skillet in a single layer, being careful not to overcrowd the pan. If necessary, cook the chicken in two batches to ensure it browns properly and doesn't steam.

Cook the chicken for 3-5 minutes per side, or until it is cooked through, nicely browned, and has some delicious charred edges. Use tongs to flip the pieces.

Once the chicken is fully cooked, return the sautéed vegetables to the skillet with the chicken. Toss everything together for 1-2 minutes to combine the flavors and heat the vegetables through.

Serve the sizzling chicken and vegetable mixture immediately. Offer with warm flour tortillas and your favorite fajita toppings such as salsa, guacamole or sliced avocado, sour cream, fresh chopped cilantro, and lime wedges for squeezing.