Coat a large baking dish with 1 tbsp of the olive oil. On the bottom of your dish, arrange lemon slices in a single layer.
Combine the remaining oil, lemon juice, garlic, salt, and pepper in a large bowl. Coat the green beans, potatoes and chicken in the oil mixture. Start by adding the green beans first. Toss to coat. Then, using tongs, remove the green beans and place them on top of the lemon slices.
Next, add the potatoes to the olive-oil mixture and toss to coat. Using your tongs again, arrange the potatoes over the green beans, along the inside edge of the dish. Last, coat the chicken in the oil mixture and place in your dish. Pour any remaining olive-oil mixture over the chicken.
Cook at 350°F for approximately 1 hour and 15 minutes (or until potatoes and veggies look soft and chicken cooked through). Serve warm.