Preheat oven to 400°F (200°C) and lightly grease a large baking dish or sheet pan.
In a large bowl, toss potatoes with half the olive oil, half the garlic, salt, pepper, and half the Parmesan.
Spread potatoes in the baking dish. Roast for 15 minutes.
Meanwhile, brush chicken thighs with remaining olive oil, garlic, Italian seasoning, and Parmesan.
After 15 minutes, place chicken on top of the potatoes and return to oven.
Bake for an additional 25–30 minutes or until chicken is fully cooked and potatoes are golden.
Garnish with chopped parsley and serve hot.