Add sugar, oil, vinegar, soy sauce, salt, and black pepper to a jar with a tight-fitting lid; shake until well blended. Set aside.

Break ramen noodles into small pieces; set aside. Discard flavor packet.

Melt butter in a skillet over medium heat. Add pecans and noodles; cook and stir until browned, about 5 minutes. Drain on paper towels; let cool.

Toss broccoli, romaine lettuce, green onions, pecans, and noodles together in a bowl. Add 1 cup, or more, dressing; toss to coat.