Preheat the oven: Set your oven to 425°F (220°C). Line a large sheet pan with parchment paper for easy cleanup.
Season the chicken: In a large bowl, combine the chicken pieces with oil, ranch seasoning, garlic powder, onion powder, smoked paprika (if using), salt, pepper, and lemon juice.
Toss until evenly coated. Let it sit for 10–15 minutes while you prep the veggies.
Prep the veggies: In another bowl, add broccoli, cauliflower, zucchini, and bell pepper. Drizzle with oil, sprinkle on ranch seasoning, garlic powder, salt, and pepper.
Toss until everything is lightly coated.
Arrange on the sheet pan: Spread the seasoned chicken on one side and the veggies on the other. Give each enough space so they roast instead of steam. Use two pans if crowded.
Roast: Bake for 18–22 minutes, flipping the chicken and stirring the veggies halfway.
Chicken is done when it’s golden and reaches an internal temperature of 165°F (74°C).
Optional broil: For extra browning, broil for 2–3 minutes at the end. Keep an eye on it to avoid burning, especially the zucchini.
Rest and finish: Let everything rest for 5 minutes. Taste and adjust salt.
Add a squeeze of lemon for brightness.
Portion for meal prep: Divide into 4–5 airtight containers. Drizzle with a little sugar-free ranch or pack it on the side. Garnish with chopped parsley or chives.