Prepare the oven: Heat your oven to 425°F and line a large rimmed sheet pan with parchment paper to prevent sticking and make cleanup easier.

Sprinkle the potatoes with half of the salt, pepper, garlic powder, and dried oregano, then toss them with your hands or a spatula until every piece is coated.

Spread the potatoes into a single layer across the pan, leaving small gaps between the pieces so they roast and brown instead of steaming.

Start the roast: Slide the sheet pan into the oven and roast the potatoes for 20 minutes while you prepare the chicken.

Prepare the chicken: Use paper towels to pat the chicken thighs very dry on both sides; removing moisture is the secret to getting the skin crispy.

In a small bowl or on a plate, rub the remaining tablespoon of olive oil and the rest of the seasonings over the chicken thighs.

Combine on the pan: Carefully remove the hot sheet pan from the oven and use a spatula to move the potatoes toward the edges of the pan to make room in the center.

Place the chicken thighs skin-side up in the center of the pan, then scatter the pitted olives and lemon slices into the gaps around the meat and potatoes.