Place the chicken breasts at the bottom of the slow cooker and drizzle with olive oil. Add the diced tomatoes, black beans, corn, cumin, chili powder, salt, and pepper on top. Pour in the chicken broth to cover the ingredients.
Cover the slow cooker and cook on low for about 4 hours, until the chicken is tender and easily shredded. The kitchen will fill with a rich, fragrant aroma and the mixture will simmer gently.
Remove the cooked chicken breasts from the slow cooker and shred them into bite-sized pieces using two forks. Return the shredded chicken to the soup and stir to combine. Let it cook uncovered for an additional 15 minutes to allow the flavors to meld.
Taste and adjust salt, pepper, or spice levels if desired. The soup should look thickened and bubbling around the edges, with vibrant colors from the tomatoes and beans.
Ladle the hot soup into bowls and sprinkle generously with shredded cheese. Top with tortilla chips, chopped cilantro, and squeeze fresh lime juice for added brightness.
Serve immediately and enjoy a comforting, vibrant bowl of chicken tortilla soup with a variety of crispy and fresh toppings that add texture and flavor.