In a large pot, heat the olive oil over medium heat.
Add the sweet potatoes and onion and cook for about 5 minutes.
Add in garlic, chili powder, chipotle powder, salt and pepper.
Add the stock, tomatoes, black beans and quinoa and bring to a boil. Stir everything to combine.
Reduce heat to a simmer and cover the pot. Cook for 45-60 minutes or until quinoa is fully cooked and sweet potatoes are soft.
Add the lime juice and remove the pot from heat.
Garnish with avocado.