Preheat oven to 350°F.
Arrange the green beans, chicken, and potatoes in rows on a rimmed baking sheet or 9x13 baking dish.
Place the butter pats evenly over the top.
In a small bowl, stir together the oregano, salt, garlic powder, onion powder, parsley, pepper, basil, thyme, celery salt, and mustard seed.
Sprinkle the dried herb seasoning blend evenly over everything on the pan.
Bake for 50-60 minutes, until chicken is cooked through and potatoes and green beans are tender.
Let cool 5 minutes before serving.