Heat olive oil in a large skillet over medium heat.
Add the diced onions and bell peppers; sauté until they soften.
Stir in minced garlic and cook until fragrant.
Add ground beef to the skillet, breaking it up as it cooks.
Season with chili powder, cumin, salt, and pepper; mix well.
Incorporate the diced sweet potatoes and diced tomatoes; stir.
Cover the skillet and let simmer for 15-20 minutes until sweet potatoes are tender.
Adjust seasoning to taste, adding more salt or pepper if needed.
Serve warm, garnished with fresh cilantro.