In a large skillet over medium-high heat, cook the ground beef, breaking it into crumbles, until browned and internal temperature reaches 160°F (71°C), about 5-6 minutes. Drain excess fat if needed.
Add diced onion to the skillet and cook until translucent, 3-4 minutes. Stir in garlic and cook for 30 seconds until fragrant.
Add uncooked rice, cumin, chili powder, and smoked paprika. Stir constantly for 1 minute to toast the rice and coat the grains in oil and spices.
Pour in diced tomatoes with their juices, beef broth, black beans, and corn. Season with salt and pepper to taste. Stir to combine.
Bring the mixture to a boil, then reduce heat to low. Cover with a tight-fitting lid and simmer for 18-20 minutes, or until rice is tender and liquid is absorbed.
Remove skillet from heat. Fluff the rice mixture with a fork, sprinkle shredded cheese evenly on top, and cover again. Let sit for 5 minutes to melt the cheese and let flavors settle.
Top with chopped cilantro, diced avocado, and a dollop of sour cream if desired. Serve hot directly from the skillet.