Melt 2 tablespoons butter in a skillet over medium-high heat. Add 8 ounces trimmed green beans and 4 carrots (cut into sticks); season with salt and pepper. Add 1/2 cup chicken broth; reduce the heat to medium, cover and simmer until tender, 6 minutes. Add 1/4 cup chopped chives, 1 tablespoon chopped tarragon, 2 teaspoons white wine vinegar and 1 teaspoon sugar. Cook 3 more minutes.