In a large pot or Dutch oven, heat olive oil over medium-low heat. Add onion and cook until translucent, stirring occasionally, about 2 to 3 minutes. Add garlic and stir until fragrant, about 30 seconds.
Increase heat to medium and add olive oil and sweet potatoes. Cook for another 5 minutes, stirring occasionally.
Stir in chili powder, cumin, oregano, paprika, salt, black pepper and tomato paste. Cook, stirring, for about 2 to 3 minutes to integrate flavours.
Stir in diced tomatoes, stock, quinoa and black beans. Reduce heat to a low simmer and cook until quinoa and sweet potatoes are soft, about 25 minutes.
Garnish with lime juice and chopped cilantro. Serve.