Heat oil in large saucepan or Dutch oven over medium-high heat. Add chopped sweet potatoes and onion. Cook, stirring often, until onion softens, about 5 minutes.
Add garlic, chili powder, cumin, chipotle and salt. Cook, stirring constantly, for 30 seconds. Add water and bring to a simmer. Cover, reduce heat to medium-low and simmer until sweet potato is cooked, about 10-12 minutes.
Stir in beans, tomatoes, and lime juice from 1/2 lime. Let simmer for about 5 minutes. Remove from heat.
Top with chopped avocado, shredded cheese, and/or tortilla chips.