Prep the pan and oven: Heat the oven to 400°F (205°C).
Line a large sheet pan with parchment paper or lightly grease it with olive oil.
Season the chicken: Pat the chicken dry with paper towels. In a bowl, toss chicken with 1 tablespoon olive oil, 1 1/2 tablespoons ranch seasoning, a pinch of pepper, and paprika if using. Set aside while you prep the broccoli.
Dress the broccoli: In a separate bowl, toss broccoli florets with 2 tablespoons olive oil, remaining ranch seasoning, minced garlic, and a small pinch of salt.
Add pepper if you like.
Arrange on the sheet pan: Spread broccoli in a single layer around the edges. Place chicken pieces in the center with a little space between them so air can circulate.
Bake: Roast for 15 minutes. Pull the pan out, stir the broccoli, and flip the chicken if you want even browning.
Add Parmesan and finish: Sprinkle Parmesan over the broccoli and a light dusting over the chicken.
Return to the oven for 8–12 minutes more, until the chicken reaches 165°F (74°C) in the thickest part and the broccoli is tender with crisp edges.
Rest and brighten: Let chicken rest for 5 minutes. Grate lemon zest over the pan or serve with lemon wedges. Garnish with chopped parsley or chives.
Serve: Plate chicken with a generous scoop of broccoli.
Spoon any pan juices over the top for extra flavor.