Preheat oven to 425°F and line a large sheet pan with parchment paper.
In a large bowl, combine chicken, potatoes, and broccoli. Drizzle with olive oil and lemon juice.
Sprinkle with black pepper, garlic powder, and salt. Toss everything together until well coated.
Spread mixture evenly on the sheet pan in a single layer. Tuck lemon slices around the chicken and veggies.
Roast for 22-25 minutes, stirring halfway through, until chicken reaches 165°F and potatoes are tender.
Garnish with fresh parsley and serve immediately with extra lemon wedges if desired.