1½ pounds sweet potatoes (about 2 medium), peeled and cut into ½-inch pieces (4¾ cups)
1 (14 ounce) can no-salt-added petite-diced tomatoes
1 (15 ounce) can low-sodium black beans, rinsed
3 tablespoons lime juice (from 1 lime)
3 medium radishes, halved and thinly sliced
¼ cup unsalted roasted pepitas (hulled pumpkin seeds)
½ cup crumbled queso fresco (3 oz.; see Tip)
1 medium avocado, chopped
Heat oil in a large pot over medium heat. Add tortilla strips and cook, stirring occasionally, until golden brown and crispy, about 5 minutes. Transfer with a slotted spoon to a paper-towel-lined plate. Sprinkle with ¼ tsp. salt.
Add poblano, onion, chili powder, and the remaining ½ teaspoon salt to the pot. Cook, stirring, until the vegetables are beginning to soften, about 2 minutes. Stir in broth, sweet potatoes, tomatoes (with their juice), and beans. Bring to a simmer. Cover and simmer, stirring occasionally, until the sweet potatoes have softened, about 20 minutes.
Stir lime juice into the soup. Ladle into 6 bowls and top each serving with radish slices, pepitas, queso fresco, avocado, and the tortilla strips.
Tip: Look for queso fresco, a mild Mexican cheese, in the dairy section of your grocery store, or use feta cheese in its place.