The secret to the best cheese enchiladas possible is all in the tortilla. The main problem people have is tortillas that are unpleasantly soggy and/or falling apart. Luckily, avoiding this problem is simple.  First of all, make sure that you are working with corn, not flour, tortillas. After that, the secret is to briefly cook the tortillas in hot oil before rolling them with fillings.  The oil helps create a barrier that prevents the tortillas from soaking up too much of the chili gravy and becoming soggy. At the same time, warming the tortillas will make them pliable and keep them from breaking apart while filling.