In a small bowl, stir together ½ tablespoon of the oil, the garlic powder, lime juice, chili powder, cumin, and salt. Add the chicken breast, toss, and let sit in the marinade for 1 to 2 hours.
Remove the chicken from the marinade, place in a skillet, and cook over medium heat. When it's done, let cool, then dice it into cubes or small pieces.
Add the chopped pepper and a small amount of the oil to the skillet. Cook until tender. Return the chicken to the skillet with the peppers and simmer on low heat.
In another large skillet, add the riced cauliflower and remaining oil and sauté over medium heat while stirring. After a couple of minutes, reduce heat to low, cover, and simmer for 3 to 5 more minutes. Remove the lid, give the cauliflower a stir, and let the moisture evaporate.
Assemble the bowls by scooping a cup of cauliflower rice into each bowl, then top with the chicken mixture, tomatoes, avocado, cheese, onions, and cilantro. Serve warm.
