Heat olive oil in a large pot over medium heat until shimmering. Add the diced onion and cook for 4-5 minutes until translucent and beginning to soften.
Add the minced garlic and cook for 30 seconds until fragrant, being careful not to let it brown or burn.
Stir in all the spices (chili powder, cumin, smoked paprika, cayenne, and oregano) and cook for 1 minute to toast and bloom the spices, which significantly enhances their flavor.
Add the cubed sweet potatoes and stir to coat with the spice mixture. Cook for 3-4 minutes, stirring occasionally.
Pour in the vegetable broth, diced tomatoes, and green chilies, scraping any browned bits from the bottom of the pot (that’s pure flavor!).
Add the drained black beans, salt, and pepper. Stir to combine everything thoroughly.
Bring the mixture to a boil, then reduce heat to maintain a gentle simmer. Cover partially with a lid and cook for 20-25 minutes, or until the sweet potatoes are tender when pierced with a fork.
Stir in the lime juice and taste for seasoning, adjusting salt, pepper, or spice levels as needed.
Serve hot in bowls with your choice of toppings. The chili will thicken slightly as it cools.