1. In a large non-stick skillet over medium heat, add diced sweet potatoes and 1/4 cup water. Cook until tender, about 10 to 15 minutes. Add garlic and navy beans, cook 2 to 3 minutes until garlic is fragrant and beans are heated through. Add corn, paprika, cumin, chill powders and remaining water. Cook until water has evaporated, about 3 to 5 minutes.
2. To make the sauce, add yogurt, chipotle powder (more if you would like it spicier) and lime juice to a small bowl; stir until combined.
3. Serve sweet potato and bean filling on tortillas topped with avocado, chipotle sauce and cilantro.