Remove flavor packet from soup mix, and reserve for another use. Break noodles into 1/2-inch pieces.
Melt butter in a pan in a 350° oven. Add noodles and walnuts; bake, stirring occasionally, 10 minutes or until lightly browned.
Whisk together olive oil and next 4 ingredients in a large bowl. Add walnut mixture, broccoli, lettuce, and green onions, tossing to coat.