In a skillet over high heat, cook ground chicken. Stir frequently and thoroughly cook until golden brown in color, about 5-7 minutes.
Add teriyaki sauce to chicken. Add optional add-in ingredients if desired. Toss to coat everything in the teriyaki sauce. Turn skillet to simmer while you prep remaining ingredients.
Wash ribs of romaine lettice and cut each in half to form 12 lettuce cups.
Spoon teriyaki chicken into lettuce cups right before serving. Top with chopped green onions and drizzle with yum yum sauce.