In a small bowl, mix together all the sauce ingredients.
Line a rimmed baking sheet with parchment paper.
Place the chicken breasts onto the baking sheet, making sure to evenly space them out. Spoon about half of the sauce over the chicken, distributing the sauce evenly among the four chicken breasts.
Bake in the oven until the chicken is no longer pink in the center, about 20 minutes.
Place the green beans around the chicken breasts. Place the lemon slices over the green beans. Spoon the remaining sauce over the chicken breasts.
Continue baking until the green beans are tender, about 10 minutes.