Heat the olive oil in a large skillet over medium heat. Add the diced onion and bell pepper, sautéing until softened, about 5 minutes.
Add the minced garlic to the skillet and cook for another minute until fragrant.
Increase the heat to medium-high, then add the ground beef to the skillet. Cook until browned—break it up with a spatula as it cooks, about 7-10 minutes.
Drain any excess fat from the beef, then stir in the taco seasoning, salt, and pepper. Add the black beans and corn, cooking for an additional 2-3 minutes until heated through.
To build the bowls, start with a base of cooked brown rice, then top with the seasoned beef mixture.
Add diced avocado, cherry tomatoes, and shredded cheddar cheese on top of the beef.
Garnish with fresh cilantro and serve with lime wedges for squeezing over the top.
Notes
Feel free to customize toppings based on your preference.