Toast the cumin seeds in a dry skillet over medium heat until fragrant, about 1 minute, then grind them into a powder using a mortar and pestle or spice grinder.
In a large pot, heat the olive oil over medium heat, then sauté the chopped onion and minced garlic until they soften and become fragrant—about 3-4 minutes.
Stir in the toasted cumin powder and smoked chili powder, letting the spices toast slightly with the vegetables, releasing their aroma—about 30 seconds to 1 minute.
Add the chicken broth and pumpkin puree to the pot, stirring until the mixture is smooth and heated through. Bring it to a gentle simmer and let it cook for about 15 minutes to meld the flavors.
While the soup simmers, preheat your oven's broiler, then spread the tortilla strips on a baking sheet. Toast them under the broiler until golden and crispy, about 2-3 minutes, tossing halfway through for even browning.
Add the shredded chicken to the soup, stirring to incorporate, and season with salt and pepper to taste. Let everything simmer for another 5 minutes until heated through.
Ladle the hot soup into bowls, then top generously with crispy tortilla strips, chopped cilantro, a dollop of sour cream or Greek yogurt, and a squeeze of fresh lime juice for bright flavor.
Serve immediately, encouraging everyone to mix in the toppings and enjoy the comforting blend of smoky, spicy, and creamy flavors in each spoonful.
