Preheat oven to 450 degrees with rack in upper third. Season chicken on both sides with salt and pepper.
Toss potatoes with 2 tablespoons oil; season with salt and pepper. Arrange, shingled, in a shallow 9-by-13-inch baking dish; bake until just tender and edges are golden, 10 to 15 minutes.
Stir together tomatoes, cinnamon, and oregano; season with salt and pepper. Pour mixture over potatoes; scatter with olives, shallots, and oregano sprigs. Top with chicken and drizzle with remaining 1 tablespoon oil. Bake until chicken is browned and crisp and a thermometer inserted into thickest parts (without touching bones) reaches 165 degrees, about 25 minutes. Serve.
Preheat oven to 450 degrees with rack in upper third. Season chicken on both sides with salt and pepper.
Toss potatoes with 2 tablespoons oil; season with salt and pepper. Arrange, shingled, in a shallow 9-by-13-inch baking dish; bake until just tender and edges are golden, 10 to 15 minutes.
Stir together tomatoes, cinnamon, and oregano; season with salt and pepper. Pour mixture over potatoes; scatter with olives, shallots, and oregano sprigs. Top with chicken and drizzle with remaining 1 tablespoon oil. Bake until chicken is browned and crisp and a thermometer inserted into thickest parts (without touching bones) reaches 165 degrees, about 25 minutes. Serve.