Prep your vegetables. Dice the onion and bell pepper, mince the garlic, and peel and cube the sweet potatoes into roughly 1/2-inch pieces so they cook evenly.
Warm the pot. In a large heavy pot or Dutch oven, heat 1–2 tablespoons of olive oil over medium heat until shimmering.
Sauté the aromatics. Add onion and bell pepper with a pinch of salt.
Cook 4–5 minutes, stirring, until softened and lightly translucent. Add garlic and cook 30 seconds until fragrant.
Bloom the spices. Stir in chili powder, cumin, smoked paprika, coriander, and cocoa powder. Cook 30–60 seconds to toast the spices.
This boosts flavor and aroma.
Add the base. Stir in tomato paste and cook 1 minute. Add crushed tomatoes, black beans, and sweet potatoes. Pour in 2 cups of broth to start and stir well, scraping up any browned bits.
Simmer gently. Bring to a simmer, then reduce heat to medium-low.
Cover and cook 15 minutes, stirring occasionally. Add more broth as needed for your preferred thickness.
Check the sweet potatoes. Cook another 10–15 minutes, uncovered if you want a thicker chili, until the sweet potatoes are tender but not mushy. Taste and season with salt and pepper.
Finish with brightness. Stir in the juice of half a lime, then taste.
Add more lime or a pinch of sugar if you want to balance acidity. Adjust heat with cayenne or chopped chipotle if desired.
Serve and garnish. Ladle into bowls and top with cilantro, avocado, Greek yogurt, cheese, and a few crushed tortilla chips for crunch.