Heat the olive oil in a heavy pot over medium heat.

Add the turkey sausage, onion, and garlic to the pot, and cook until the onions are soft and translucent. Stir in the sweet potatoes and cook 3-4 minutes.

Add the chicken broth, diced tomatoes, tomato sauce, black beans, and chili beans, and stir to combine. Add the chili powder, cumin, salt, and pepper.

Bring the mixture to a simmer. Reduce heat and simmer uncovered 20-25 minutes, stirring occasionally, until the sweet potatoes are tender and easily pierced with a fork, and the chili has thickened. Serve hot, topped with a dollop of sour cream and a sprinkle of cheese.