Remove seasoning packet from ramen noodles, and reserve for another use. Break noodles into pieces.
Melt butter in a large skillet over medium-high heat; add ramen noodles and walnuts, and sauté until lightly browned. Drain on paper towels.
Toss together noodle mixture, broccoli, lettuce, and green onions in a large bowl; add 1/4 cup Sweet-and-Sour Dressing, tossing to coat. Serve with remaining dressing.