1. Pat chicken breasts dry and season with chili powder, cumin, garlic powder, salt, and pepper. Heat olive oil in a large skillet over medium-high heat. Add chicken and cook for 6-8 minutes per side, or until cooked through and no longer pink in the center. Remove chicken from skillet and let rest for 5 minutes. Then, dice or shred the chicken. In a bowl, combine cooked brown rice, black beans, corn, red onion, and cilantro. Assemble the burrito bowls by distributing the rice mixture into serving bowls. Top with diced chicken, avocado, and a squeeze of fresh lime juice. Serve immediately with optional toppings like salsa, sour cream, or shredded cheese.