In a heavy saucepan or skillet, brown the ground beef and onions. Season the ground beef mixture with garlic salt and set aside.
In a skillet, fry the tortillas in vegetable oil. Spoon some meat mixture and cheese into the center of each tortilla, roll them up and arrange them in a 9x13 inch baking dish or oblong pan. Pour the enchilada sauce over the rolled enchiladas and top with any remaining meat or cheese.
Bake in the preheated 350 degrees F (175 degrees C) for 20 to 30 minutes.