Preheat oven to 425°F (220°C).
Toss sweet potato cubes with 1 tablespoon olive oil, 1 teaspoon chili powder, 1/2 teaspoon cumin, 1/2 teaspoon paprika, garlic powder, onion powder, salt, and pepper.
Spread sweet potatoes on a baking sheet and roast for 25-30 minutes until tender and slightly caramelized.
Heat 2 tablespoons olive oil in a large skillet over medium-high heat.
Season beef slices with remaining spices (chili powder, cumin, paprika, salt, pepper).
Sauté beef for 4-5 minutes until cooked to desired doneness. Remove from heat.
In the same skillet, add chopped bell pepper and red onion; sauté for 3-4 minutes until softened.
Drain and rinse black beans; warm them gently if desired.
Once sweet potatoes are done, assemble bowls: start with roasted sweet potatoes as the base.
Top with sautéed beef, bell peppers, red onions, black beans, corn, and sliced avocado.
Drizzle with fresh lime juice and garnish with chopped cilantro if using.
Serve immediately and enjoy!