Cut Peppers And Onion Into Thin Slices. Do Not Dice, Leave Slices Long And Thin. Saute Peppers And Onion In A Small Amount Of Oil Until Tender. Add Mushrooms And Chicken. Continue To Cook On Low Heat Until Heated Through. Stir In Dry Salad Dressing Mix And Blend Thoroughly. Warm Tortillas And Roll Mixture Inside. If Desired Top With Shredded Cheddar Cheese, Diced Tomato And Shredded Lettuce.