There are lots of things that go by the name of Chili sauce, and they can be quite different. A good recipe source for Chile sauces that are common to New Mexico is "The Feast of Santa Fe" by Huntley Dent. By the way, in NM we call them Chiles.
Garlic, onions, salt, cumin, oregano, and cilantro are typical additions to chiles to make sauces. In general, the simpler the better when it comes to Chile sauce. Roasting the chile before using it in a sauce brings out its flavor.
In the fall in NM, there are chile roasters on nearly every vacant lot and in front of grocery stores. They sell 40 lb sacks of green chiles from Hatch NM, typically Big Jim or Sandia, which are a similar variety to Anaheim. They roast these chiles with a propane roaster, which is a rotating perforated metal drum over a propane flame. The roasted chiles are then dumped into a garbage bag, put in a box and taken home where they are peeled and frozen for use over the next year.
While the chiles are still hot, my wife takes one or two, puts them in a blender with some salt and garlic and blends it to a mush. This is great spread warm on fresh tortillas, french bread, crackers, chips, or on the end of your finger.
I, and other New Mexicans, make a green chile sauce that is used a bit like the French use sauces, but that is really a coarse comparison.
Sautee a chopped up medium onion in a tbsp or two of olive oil and some cumin seed. Towards the end of cooking, add some minced garlic. Add 2 tbsps of flour and stir like crazy for two minutes or so. The darker the flour gets, the darker the stew will be. Cooks will recognize this as a roux. Add a half cup of chopped roasted green chiles, salt, pepper, oregano and stir. Then add chicken broth until it is the thickness of gravy. Simmer for a half hour, adding broth so that the consistency you want is maintained. If it is too thin, simmer until it is the consistency you want. Taste and add salt and pepper to taste.
This is great as a base for stews and soups, over enchiladas, in enchiladas with the addition of some meat, on burritos, over an omelette, and on eggs as huevos rancheros.
Cook a big pile of hash browns or tater tots. heap them on a plate, crumble bacon or sausage over the whole pile. Add a fried egg or two. Smother the whole thing with green chile. grate some sharp cheddar cheese on top. Great breakfast.
MMMMmmmmmmm.......Green Chile, there is nothing like it.