In a small mixing bowl, combine the 1 ½ tsp chili powder, 1 tsp cumin, 1 tsp smoked paprika, ½ tsp garlic powder, ½ tsp onion powder, ½ tsp kosher salt, ¼ tsp black pepper, and ¼ tsp cayenne pepper (if using). Stir to mix evenly. Set aside.

Preheat your oven to 425°F. Position a rack in the upper-middle of the oven. Line a large baking sheet (18x13-inch) with aluminum foil for easy cleanup.

Slice the 1 ½ lb boneless skinless chicken breasts thinly sliced into ¼-inch strips into thin, even strips about ¼-inch thick — this is key for quick, even cooking. Slice all red bell pepper seeded and thinly sliced, 1 yellow bell pepper seeded and thinly sliced, and 1 yellow onion halved and thinly sliced into similarly thin strips so everything cooks at the same rate.

Add the 1 ½ lb boneless skinless chicken breasts thinly sliced into ¼-inch strips strips, 1 red bell pepper seeded and thinly sliced, 1 yellow bell pepper seeded and thinly sliced, and 1 yellow onion halved and thinly sliced to a large mixing bowl. Drizzle with the 3 tbsp olive oil and 2 tbsp lime juice freshly squeezed, then sprinkle the entire spice blend over the top. Toss everything together thoroughly until every piece is evenly coated.

Spread the 1 ½ lb boneless skinless chicken breasts thinly sliced into ¼-inch strips and vegetables in a single, even layer across the prepared baking sheet. Do not pile or overlap — crowding causes steaming instead of roasting. If needed, use two baking sheets.

Roast in the preheated oven for 18–20 minutes, until the 1 ½ lb boneless skinless chicken breasts thinly sliced into ¼-inch strips is cooked through (internal temperature of 165°F) and the peppers are tender with some charred edges.

For extra char and color — just like a restaurant — switch the oven to broil on HIGH and broil for 2–3 minutes, watching closely. You want caramelized, slightly blistered edges on the peppers and 1 ½ lb boneless skinless chicken breasts thinly sliced into ¼-inch strips, not burnt.

While the fajitas broil, warm your tortillas: wrap them in a damp paper towel and microwave for 30–45 seconds, or warm them one at a time in a dry skillet over medium heat for 20–30 seconds per side.

Remove the baking sheet from the oven. Squeeze a fresh lime cut into wedges wedge over the entire pan. Serve immediately straight from the pan with warm tortillas and all your desired toppings — ½ cup sour cream, 1 avocado sliced or mashed, ½ cup salsa store-bought or fresh, ½ cup shredded Mexican cheese blend, and ¼ cup fresh cilantro roughly chopped.