Preheat oven to 400°F. Coat a large baking dish or cast-iron skillet with 1 tablespoon of the olive oil. Arrange the lemon slices in a single layer in the bottom of the dish or skillet.
In a large bowl, combine the remaining oil, lemon juice, garlic, salt, and pepper; add the chicken, green beans and potatoes and toss to coat. Pour this mix into the pan and spread around evenly.
Roast for 50 minutes or until cooked through.