There has been an ongoing debate about authentic versus americanized Mexican food. To me the deciding issue is whether the food is tasty and and satisfying. My mother from Mexico cooked dishes very similarly to Chapalas. I having been going to Chapalas since the early 1990s and the food has been consistently great throughout that span of time.
The dinning area consists of booths and tables with your basic Mexican restaurant decor. The wait staff are responsive, quick and have been with the restaurant for years.
I have had the carne assada, enchiladas suezas, and chili colorado,, and all have hit the mark, being, rich, flavorful, and spicy (tasty not too hot). My favorite dish over the years has been chili verde (pork braised in a spicy green chili sauce that is acidic and savory). I have yet to find a restaurant in America that makes it better.