Pat the chicken breasts dry with a paper towel, then cut into 1 ½-inch chunks and transfer to a large mixing bowl.
In a small bowl, mix together parsley, Italian seasoning, onion powder, paprika, seasoned salt, and black pepper.
Add half of this blend to the chicken, along with 2 tablespoons of olive oil, minced garlic, lemon zest, and lemon juice.
Stir everything well to coat the chicken evenly. Cover the bowl and refrigerate for 30 minutes to marinate.
Preheat your oven to 425°F and line a large baking sheet with parchment paper for easier cleanup. Slice the baby carrots in half lengthwise and cut the baby Yukon gold potatoes in half (or quarters if they’re large).
Add the carrots and potatoes to the baking sheet along with 2 more tablespoons of olive oil and most of the remaining seasoning mix (save about 1 teaspoon). Toss until the vegetables are well coated, then roast in the oven for 20 minutes.
While that’s baking, chop the broccoli into bite-sized florets.
Once the 20 minutes are up, remove the baking sheet from the oven.
Give the carrots and potatoes a quick stir and move them to one side of the pan. On the other side, add the broccoli and a bit more minced garlic.
Drizzle with the last tablespoon of olive oil and sprinkle with the remaining seasoning. Toss to coat and mix the broccoli in with the other vegetables if desired.
Take the marinated chicken out of the fridge and discard any excess marinade. Spread the chicken pieces across the pan, making sure they aren’t overlapping so they cook evenly.
Return the pan to the oven and roast for another 15-20 minutes, or until the chicken reaches an internal temperature of 165°F and the veggies are tender. For extra color and slight charring, switch the oven to broil on high for the last 1-2 minutes, keeping a close eye to prevent burning.