Place the chicken breasts at the bottom of the crockpot, spreading them out evenly.
Add the canned diced tomatoes (with juices), chopped onion, and minced garlic over the chicken.
Sprinkle the cumin and chili powder evenly over the ingredients, then pour in the chicken broth.
Cover the crockpot and set it to low. Let everything cook for 6-8 hours until the chicken is tender and easily shredded, and the flavors meld.
Once cooked, remove the chicken breasts and shred them using two forks. Return the shredded chicken to the broth and stir well.
Taste the soup and adjust seasoning if needed. Squeeze fresh lime juice into the broth for a bright, zesty kick.
Ladle the hot soup into bowls, then top with crushed tortilla chips and chopped cilantro for crunch and freshness.
Serve immediately while steaming hot, with extra lime wedges on the side for squeezing.