Heat olive oil in a large skillet over medium heat.
Add chopped onions and bell peppers; sauté for 5-7 minutes until softened.
Stir in minced garlic; cook for an additional 1 minute.
Add diced sweet potatoes, chili powder, cumin, salt, and pepper; stir to coat.
Cover and cook for 10-15 minutes, stirring occasionally, until sweet potatoes are tender.
Mix in black beans and corn; cook for another 5 minutes until heated through.
Adjust seasoning with more salt and pepper if necessary; remove from heat.
Garnish with fresh cilantro before serving.