Preheat oven to 400 degrees 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 on the bottom of the dish or skillet.
In a large bowl, combine the remaining oil, lemon juice, garlic salt, and pepper. Add the checken, green beans, and potatoes. Toss to coat.