Air dry the tortillas: About an hour or two before you start making the soup, you will need to dry out the tortillas. Start by ripping up 4 tortillas into small pieces, and set them aside to be used in step 2. The rest of the tortillas will need to be cut into strips. Start by stacking these tortillas, and cutting them in half. Then take each half and slice them perpendicular into thin strips. Lay these strips out on a baking sheet so that they can air dry a bit.
Saute the onion, corn, chipotle, tortillas, garlic, and seasoning: Get out a large 6 quart sized pot, and add a tablespoon of oil to it. Place this over a medium high heat. Then toss in the onion, corn, and the 4 ripped tortillas from the previous step. Saute this for 3 to 4 minutes. Then add in the chipotle, garlic, and seasonings. Continue sauteing for an additional 2 minutes.
Add stock, tomatoes, and chicken: Quickly pour in the chicken stock and stir everything up. Then add in the can of tomatoes, and the cooked chicken pieces.
Let this simmer for an hour or two.
Fry the tortilla strips: Get out a medium sized pot, and pour enough oil into it so that it is filled a third of the way up. Then put this over a medium high heat. After a couple minutes test how hot the oil is by placing a single tortilla strip in it. If it begins to bubble up and make some noise, then it is ready. Once it has reached this point start frying the tortillas in small batches, and setting them aside in a bowl. Once all of the tortilla strips are fried, salt them to taste.
Serve the soup by ladling it into a bowl. Then garnish with the tortilla strips, cilantro, green onion, and a fresh squeeze of lime juice. Enjoy!