Chicken Tortilla Soup with Hatch Chiles

large summer tomatoes

extra-virgin olive oil (divided)

white onion (chopped)

garlic cloves (minced)

cumin

32- ounce box reduced-sodium chicken broth

hatch chiles (roasted, stemmed and seeded, then diced)

shredded chicken (or as much as one whole rotisserie chicken)

cilantro (chopped)

toppings: sour cream (crushed tortilla chips, chopped cilantro, avocado)