Heat the olive oil in a large skillet or Dutch oven over medium heat.

Add the ground turkey to the skillet and cook, breaking it up with a spoon, until browned, then drain any excess fat.

Add the chopped onion and diced sweet potato to the skillet, cooking for 5-7 minutes until the onion softens, then stir in the minced garlic and cook for another minute until fragrant.

Pour in the diced tomatoes (with their liquid) and chicken broth, then stir in the chili powder, cumin, cayenne pepper (if using), salt, and black pepper, and bring the mixture to a simmer.

Reduce heat to low, cover, and let it simmer for 15-20 minutes, or until the sweet potatoes are tender, stirring occasionally.

Taste and adjust seasonings as needed.

Serve hot, garnished with fresh cilantro, sliced avocado, and a dollop of Greek yogurt or sour cream, if desired.