Heat olive oil in a large skillet over medium-high heat.
Add diced onion and cook for 3-4 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add ground beef to the skillet and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Drain any excess fat from the skillet.
Stir in chili powder, ground cumin, smoked paprika, dried oregano, cayenne pepper, salt, and black pepper. Cook for 1 minute to toast the spices.
Pour in beef broth and add diced tomatoes and black beans. Stir to combine.
Reduce heat to medium-low and simmer for 8-10 minutes until the mixture thickens slightly.
While the beef mixture simmers, prepare the brown rice according to package instructions if not already cooked.
In four serving bowls, divide the cooked brown rice evenly.
Top each bowl with the beef and bean mixture.
Sprinkle shredded cheddar cheese evenly over each bowl while the beef mixture is still hot to allow it to melt slightly.
Add diced red and green bell peppers and chopped green onions on top.
Garnish each bowl with fresh cilantro, a dollop of Greek yogurt, and diced avocado.
Serve with lime wedges on the side for squeezing over the bowls.