Add your chicken breasts in a row down the middle of a 9 x 13 baking dish. If your chicken breasts are thick, cut them in half lengthwise.
Wash and cut the new potatoes into 1 to 2-inch sized pieces. Place them along one side of the chicken breasts.
If using fresh green beans, wash, dry, and trim the beans. Cut them into 2-inch sized pieces. If using canned green beans, drain off any liquid. Add the green beans down the other side of the chicken breasts.
Sprinkle the entire dish with the dry Italian Dressing Mix. (See recipe notes above for the homemade Dry Zesty Italian Dressing mix recipe.)
Cut the butter into cubes and dot the top with the butter. Cover the dish with foil and bake for 45 minutes or until the chicken reaches an internal temperature of 165º F and the potatoes are fork tender.
If you used thicker cuts of chicken or cuts with bones, the cooking time will likely need to be increased. Check after 45 minutes for doneness and adjust accordingly. Store any leftovers in an airtight container in a refrigerator.