I tried to cheat here in posting my chicken tortilla soup recipe by finding my recipe online somewhere and copying it, however, "my recipe" doesn't seem to be out there (maybe because mine is not the easy version... but it is the super tasty version).

I don't know for sure that this is exact, to be honest, I don't use a recipe, I just make it.   But this is what I do for the very best authentic chicken tortilla soup:

Take one whole chicken, put in slow cooker, cover with water (or at least 3/4 of chicken covered, about 4 cups in my slow cooker) and add some salt.  Cook overnight (or how you would normally cook your whole chicken in slow cooker or pressure cooker).  Let the chicken cool a bit, and debone.   Take half of the meat and stick it in the freezer to be used for chicken salad or something like that later on.

Take the other half of chicken meat (about 2-3 cups), add it back to the chicken broth (there should be probably 4-5 cups or so of chicken stock).

Now in another big pot (or continue to use your slow cooker), saute:

1/2 chopped onion

2 tsp. fresh minced garlic in some oil or butter until tender. 

Add and cook over medium heat, covered:

chicken and stock

2 cans (14oz ea) of chopped tomatoes 

1/4 bunch of cilantro cut up

1-2 tsp. cumino

1/2 - 1 tsp. chili powder

1 Tbsp salt

1/2 tsp pepper 

optional ingredients:

1-2 zuccini squash, sliced

1-2 c. corn (I prefer the frozen)

When it smells like heaven and the zuccini are tender, serve in bowls and top with:

tortilla chips.   I usually slice up my corn tortillas and fry them myself in olive oil or lard (yes, I did say the "L" word) for the authentic experience.

shredded cheddar cheese

slices of avacado

sour cream

sprig of fresh cilantro

We just had this tonight, and Nathan very much enjoyed that bowl of authentic tortilla soup.   Mmmm...

I should add that you can also simplify this recipe using about 4 boneless chicken breasts or boneless quarters, and just put all ingredients in slow cooker (including the 4 c of water) and cook all day (or even in a pressure cooker at the last minute and cook for 20-25 minutes for a very quick dinner).