In a small bowl, combine chili powder, cumin, smoked paprika, garlic powder, onion powder, salt, and pepper. Rub the seasoning evenly over both sides of the chicken breasts. Heat 1 tablespoon of olive oil in a large skillet over medium heat.
Add the chicken and cook for 6–8 minutes per side, or until fully cooked and the internal temperature reaches 165°F. Remove from the skillet and let rest for 5 minutes before slicing.
While the chicken cooks, warm the black beans and corn together in a small saucepan over medium heat with the remaining tablespoon of olive oil, stirring occasionally until heated through.
In a separate bowl, whisk together the sour cream, mayonnaise, lime juice, cilantro, chili powder, garlic powder, and salt. Add milk a tablespoon at a time until the sauce reaches a smooth, drizzleable consistency.
To assemble the bowls, divide the cooked rice evenly among four bowls. Top each with sliced chicken, black beans, corn, cherry tomatoes, avocado, and shredded cheese. Drizzle generously with the creamy lime sauce and sprinkle with chopped cilantro before serving.