Heat olive oil in a large heavy-bottomed pot over medium heat until shimmering.
Add diced onion and sauté for 5 to 7 minutes until translucent and soft.
Add minced garlic, chili powder, cumin, smoked paprika, and cayenne pepper; stir continuously for 60 seconds to toast spices without burning.
Incorporate diced sweet potatoes, black beans, crushed tomatoes, and vegetable broth into the pot.
Increase heat to medium-high and bring the liquid to a rolling boil.
Reduce heat to low, cover partially, and simmer for 35 to 40 minutes or until the sweet potatoes are tender when pierced with a fork.
Season with salt to taste and adjust thickness by lightly mashing a portion of the sweet potatoes against the side of the pot if a thicker consistency is desired.
Serve hot with optional garnishes such as cilantro, lime, or avocado.