Pat the chicken breasts dry with paper towels, trim away excess fat, and cut into 1/2-inch pieces. Transfer to a medium bowl.

In a small bowl, combine the parsley, oregano, garlic powder, onion powder, paprika, seasoned salt, and pepper, stirring in the red pepper flakes if using. Add half of the seasoning mixture to the chicken with 2 tablespoons olive oil and the zest and juice of one lemon. Toss well, cover, and refrigerate for 30 minutes.

Preheat the oven to 425°F. Line a large sheet pan (15 x 21 inches) with parchment paper.

Slice the carrots lengthwise, halve the baby potatoes, and coarsely chop the onion. Arrange on the sheet pan, drizzle with 2 tablespoons olive oil, and sprinkle with most of the remaining seasoning mixture, reserving 1 teaspoon. Toss to coat and roast for 20 minutes.

While the vegetables roast, chop the broccoli into bite-sized florets.

Remove the pan from the oven and push the roasted vegetables to one side. Add the broccoli and minced garlic to the other side with the remaining tablespoon of olive oil and the last teaspoon of seasoning. Toss to coat, then combine with the other vegetables.

Remove the chicken from the refrigerator and drain away the excess marinade. Arrange the chicken pieces on the baking sheet in a single layer, not overlapping.

Return the pan to the oven and roast for 15-20 minutes, until the chicken reaches an internal temperature of 165°F and the vegetables are tender.

Switch the oven to high broil for 1-2 minutes to lightly brown the vegetables and chicken, watching closely to prevent burning.

Remove the sheet pan from the oven, sprinkle generously with freshly grated Parmesan cheese, and serve immediately. For meal prep, divide cooked quinoa or rice among four containers and top each with chicken and vegetables.