Whisk orange juice, broth and cornstarch in a small bowl. Heat oil in a large nonstick skillet over medium-high heat. Add carrots and cook, stirring constantly, until slightly softened, about 3 minutes. Stir the juice mixture and add to the carrots along with butter and salt. Cover and continue cooking, stirring occasionally, until the butter melts and the carrots are tender, 5 to 6 minutes.