01 - Set oven to 425°F and allow it to preheat completely.
02 - In a large mixing bowl, combine chicken thighs, sliced bell peppers, and sliced red onion. Pour in olive oil and sprinkle with Cajun seasoning. Toss thoroughly to ensure all ingredients are coated evenly.
03 - Spread the seasoned chicken and vegetables on a baking sheet in a single layer. Roast for 25 minutes, or until chicken is cooked through to an internal temperature of 165°F and vegetables are tender.