In a bowl, combine olive oil, adobo sauce, smoked paprika, garlic powder, onion powder, salt, and pepper. Add the chicken thighs and coat well. Let marinate for at least 30 minutes (or overnight for more flavor).
Rinse the brown rice under cold water. In a saucepan, combine the rice with 2 cups of water and a pinch of salt. Bring to a boil, then reduce heat to low, cover, and simmer for about 35-40 minutes until tender. Fluff with a fork and set aside.
Heat a grill or skillet over medium-high heat. Cook the marinated chicken thighs for 6-7 minutes on each side until fully cooked and internal temperature reaches 165°F (75°C). Remove from heat and let rest before slicing.
While the chicken is cooking, prepare the toppings. In a bowl, combine corn, black beans, cherry tomatoes, and chopped cilantro. Squeeze lime juice over the mixture and season with salt to taste.
In serving bowls, start with a base of brown rice. Layer on the sliced chicken, black bean and corn mixture, and avocado slices.
Top each bowl with a dollop of sour cream or Greek yogurt, if desired.
Notes
Marinate the chicken overnight for enhanced flavor.