#1 Preheat oven to 425?. #2 On a large sheet pan toss together tortilla strips and 1 tablespoon oil. Spread out strips and bake until crispy, about 10 minutes. Set aside. #3 In a large saucepan or Dutch oven, heat remaining 2 tablespoons oil over medium heat. Add onion and sauté until softened, about 5 minutes. Add garlic, chipotles, and chili powder and cook, stirring, 1 minute more. #4 Add tomatoes, beans, and broth. Bring soup to a simmer and cook for 15 minutes to allow flavors to meld. #5 Serve soup in bowls, letting everyone choose their own toppings.