Peel and dice the sweet potato into small 1/2-inch cubes.
In a large pot, heat the olive oil over medium heat and add the ground turkey, onion, and bell pepper.
Cook until the turkey is browned and the vegetables are softened, breaking the meat into small crumbles.
Stir in the chili powder, cumin, garlic powder, sea salt, and black pepper to toast the spices.
Add the diced sweet potatoes, rinsed black beans, tomato puree, and water to the pot.
Bring the mixture to a boil, then reduce heat to low, cover, and simmer for 20 minutes until the sweet potatoes are fork-tender.
Remove from heat and serve in a bowl topped with the Greek yogurt for a cool, creamy finish.