Step #1 Saute chicken in vegetable oil with garlic salt until just done.
Step #2 Spread each tortilla with cream cheese; divide chicken, onion, spinach, & tomatoes between tortillas; roll enchiladas & place seam-side down in 9x13" baking dish that has been lightly sprayed with no-stick cooking spray.
Step #3 Pour enchilada sauce evenly over enchiladas then top this with grated cheese; bake this at 350° degrees for 15 mins until cheese is melted.
Step #4 NOTE: Only six of these thick enchiladas will fit in my 9x13" baking dish, & so I also use a large loaf pan to hold the last two.