Heat olive oil in a large deep skillet or Dutch oven over medium-high heat.
Add diced onion and cook for 2-3 minutes until softened.
Add ground beef and cook, breaking it up with a spoon, until browned and cooked through, about 5-6 minutes.
Add minced garlic and cook for 1 minute until fragrant.
Stir in chili powder, ground cumin, smoked paprika, salt, black pepper, and crushed red pepper flakes until the beef is evenly coated with the spices.
Add rinsed rice to the pot and stir to combine with the beef and spices.
Pour in beef broth, water, diced tomatoes with green chilies (including the liquid), black beans, and frozen corn.
Bring the mixture to a boil, then reduce heat to low and cover with a tight-fitting lid.
Simmer for 18-20 minutes or until the rice is tender and liquid is absorbed.
Remove the pot from heat and let it sit, covered, for 5 minutes.
Fluff the rice mixture with a fork and sprinkle shredded cheddar cheese on top.
Cover again for 2 minutes to allow the cheese to melt.
Garnish with chopped cilantro, avocado slices, lime wedges, and a dollop of sour cream before serving.