1. Preheat your oven to 400 F (200 C). Line a large baking sheet with parchment paper for easy cleanup.

2. In a medium bowl, combine the cubed chicken breast with 1 tablespoon of olive oil, Italian seasoning, garlic powder, onion powder, salt, and black pepper. Toss well to ensure every piece of chicken is evenly coated.

3. In a separate large bowl, combine the bell pepper, zucchini, cherry tomatoes, and red onion. Drizzle with the remaining 1 tablespoon of olive oil and toss gently until all the vegetables are lightly coated.

4. Spread the seasoned chicken and vegetables in a single layer on the prepared baking sheet. Do not overcrowd the pan; use two baking sheets if necessary.

5. Place the baking sheet in the preheated oven and roast for 20-25 minutes. About halfway through (around 10-12 minutes), gently stir the chicken and vegetables to promote even cooking and browning. The chicken should be cooked through, with no pink remaining, and the vegetables should be tender-crisp with slightly browned edges.

6. To confirm the chicken is fully cooked, it should register 165 F (74 C) with a meat thermometer. Remove from the oven, garnish with fresh chopped parsley if desired, and serve immediately.