Place chicken breast and broth into a large saucepan and bring to a boil. Boil for about 8-10 minutes, until chicken is cooked through and no longer pink. Leave the vegetable broth in the saucepan and remove the cooked chicken. Shred into small pieces.
Add the can of diced tomatoes to the vegetable broth and bring to a boil. Add in the shredded chicken, chilies, onion, bell pepper, garlic, cumin, salt and pepper. Return the pot to a boil, then reduce to a simmer and cook uncovered for 30-40 minutes.
While the soup is simmering, preheat the over to 375ºF. Cut the tortillas into thin 1/4-inch strips and lay on a baking sheet. Drizzle with olive oil and season with sea salt and pepper, then bake for 10-12 minutes, until lightly browned and crisp.
Serve warm soup topped with crisp tortilla strips and shredded cheese.