In a large mixing bowl, combine the chicken breasts with olive oil, fajita seasoning, minced garlic, salt, and pepper. Toss well to coat the chicken evenly.
On a large sheet pan, arrange the seasoned chicken breasts in the center. Surround them with the sliced bell peppers and red onion, ensuring everything is well distributed.
Drizzle a bit more olive oil over the vegetables and season with salt and pepper. Toss them lightly on the sheet pan for even flavor.
Bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through (internal temperature should reach 165°F/75°C) and the vegetables are tender and slightly caramelized.
Remove the sheet pan from the oven and let it rest for a few minutes. Slice the chicken into bite-sized pieces.
Serve your fajita chicken and vegetables warm, garnished with fresh cilantro and lime wedges on the side.
Notes
Feel free to customize the vegetables based on your preference.