1. Preheat the oven to 400°F. Lightly spray a baking sheet with nonstick spray.
2. Place the chicken onto the baking sheet. In a small bowl, whisk the sesame oil and soy sauce. Brush the mixture evenly over the chicken.
3. Arrange the red bell peppers, yellow bell peppers, carrots, broccoli and red onion on the baking sheet. Drizzle the olive oil over the vegetables and toss gently to coat; season with salt and pepper.
4. Roast until the vegetables are tender and the chicken is fully cooked, 23 to 25 minutes. Remove from the oven and garnish with parsley.