Heat a tablespoon of oil in a large pot over medium heat.
Add diced onion and cook until translucent.
Stir in minced garlic and cook for another minute.
Add chopped tomatoes and chili powder, stirring well.
Pour in the broth and bring to a boil.
Reduce heat and let simmer for 15 minutes.
While the soup simmers, cut tortillas into strips.
In a separate pan, fry tortilla strips until golden and crispy.
Season the soup with salt to taste.
Serve hot, topping each bowl with crispy tortillas, avocado, cheese, and cilantro.