1 tablespoon olive oil 1 tablespoon unsalted butter 1 boneless skinless chicken breast, chopped 1/4 teaspoon salt 1/4 teaspoon pepper 3 tablespoons unsalted butter 1/2 sweet onion, diced 1 cup baby gold potatoes, diced 4 tablespoons flour 1/2 summer squash, sliced into rounds then cut in half 1/2 cup fresh green beans