Combine sour cream, soup, green chilies in saucepan. Heat over medium heat - do not boil. Soft fry tortillas. To soften in microwave, lightly brush each tortilla with oil and stack up on late, cover with plastic wrap and microwave for 30- 45 seconds.
Place in each tortilla: 2 tablespoons of mixture, onion to taste, chicken, and cheese. Roll up and place in baking pan. Pour remaining sauce over all and top with additional cheese.
Bake at 350° for 30 minutes. Can be frozen and reheated.