Preheat oven to 350 degrees. Mix chicken, onion, salsa, cheese, sour cream, and cumin together. Salt and pepper. Spoon chicken mixture on tortillas. Wrap tortillas and place them in a large baking pan. Combine salsa, yogurt, sour cream, and green onions in another bowl. Pour sauce over tortillas. Sprinkle with cheese and bake for 30 minutes.