Preheat oven to 425°F (220°C). Toss sweet potatoes (whole) with 1 tbsp oil, roast 30–40 minutes until fork-tender.
Remove potatoes; let cool slightly. Scoop out flesh and roughly mash; reserve skins.
While potatoes roast, sauté onion in a skillet with cumin and paprika until soft. Add black beans and mashed sweet potato, warm through, season.
Toss reserved skins with 1 tbsp oil, salt, and pepper; spread on baking sheet and roast 10–15 minutes until crisp.
Warm tortillas, fill with sweet potato–bean mixture, top with cilantro, a squeeze of lime, and a dollop of yogurt. Serve chips alongside.