Heat olive oil in a large pot over medium heat. Add onions and bell pepper, cooking until softened (about 5 minutes).
Add garlic and cook for another minute until fragrant.
Add chicken breasts, fire-roasted tomatoes, green chilies, chicken broth, cumin, chili powder, and oregano. Bring to a boil.
Reduce heat, cover, and simmer for 25-30 minutes until chicken is cooked through.
Remove chicken and shred using two forks. Return to pot.
While the soup is simmering, prepare the tortilla strips. Cut tortillas into thin strips and either air fry at 375°F for 5-6 minutes or bake at 375°F for 10-12 minutes until crispy.
Season soup with salt and pepper to taste.
Serve hot, topped with crispy tortilla strips and your choice of garnishes.