Heat olive oil in a large skillet over medium-high heat.
Add the chopped onion and cook for 3-4 minutes until softened.
Add the minced garlic and cook for 30 seconds until fragrant.
Add the ground beef to the skillet and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Stir in chili powder, ground cumin, smoked paprika, cayenne pepper, salt, and black pepper. Cook for another 1-2 minutes to toast the spices. Remove from heat and set aside.
In a medium saucepan, bring 2 cups of water to a boil.
Add the rice, reduce heat to low, cover, and simmer for 15 minutes or until rice is tender and water is absorbed.
Remove rice from heat and let it sit covered for 5 minutes, then fluff with a fork.
In a small bowl, mix sour cream, fresh lime juice, and 1/4 teaspoon salt until smooth. Set aside.
To assemble the bowls, divide the cooked rice evenly among four bowls.
Top each bowl with seasoned ground beef, black beans, corn, shredded cheddar cheese, diced tomato, diced avocado, and chopped cilantro.
Drizzle each bowl with the lime sour cream sauce.
Serve immediately and enjoy.