Note: This recipe will make more shredded chicken than you need for the soup. Use the extra shredded chicken for the Real Mexican Tacos recipe.
In a large stockpot over medium heat, combine chicken, onion, garlic, salt, and bouillon cube. Fill pot with water until chicken is covered by about 1 inch. Bring to a gentle simmer and cook until chicken tender and fully cooked. Remove chicken from pot and let cool completely. Skin and bone chicken, then shrew meat into chunks using 2 forks.
Stack 3-4 corn tortillas at a time and cut into 3" by 1/2" strips. Spread out on a plate or cookie sheet and allow to air dry for 5 minutes. Peel cheese into long shreds.
Heat about a 1/2 cup of oil in a skillet over medium heat. To test if it's hot enough to fry, drop one tortilla piece in and see if it bubbles and sizzles. Once oil is hot, fry tortilla strips in batches, careful not to crowd pan. Stir and flip strips to make sure they brown evenly. Remove with a strainer when strips become crispy but not too dark brown. Drain on a paper towel-lined plate.
When ready to serve soup, reheat chicken broth until almost boiling. Place tortilla strips and shredded string cheese in soup bowls and pour hot broth over them. Top with shredded chicken, sour cream, and any other garnishes you may like. Makes 6 to 8 servings. Enjoy!