Remove excess fat from the chicken breasts. Slice the breasts in half horizontally and pound halves to an even thickness (this helps them cook evenly) Add the chili powder, garlic powder, cumin, oregano, 1 teaspoon salt and 1/2 teaspoon pepper to a small bowl. Stir. Pat chicken dry with a paper towel and then sprinkle and press this seasoning mixture evenly onto all sides of the chicken pieces.
(Read Note 2) Preheat a grill to medium-high heat (about 400 degrees F.) Generously oil the grill or ridges of grill pan (I drench a rolled-up paper towel in vegetable oil and, holding it with tongs, rub it over the grill grates.)
Place the chicken onto the grill and grill 5 to 6 minutes per side, until the chicken is cooked. Remove the chicken from the grill and let rest for 10 minutes. Chop the chicken into small, bite-sized pieces.
Cook rice or quinoa in chicken broth, stock, or water. Once cooked, fluff with a fork and add the juice of a lime (to taste; I add all of it) and cilantro to taste.
Separate the rice or quinoa and chopped chicken into 4 separate plates or bowls. Add your favorite toppings evenly among the bowls. Add the sauce and enjoy!
For the sauce: whisk all sauce ingredients together. Season to taste with salt and pepper.
Note 1: for a smoky flavor use chipotle chili powderNote 2: for alternate cooking methods check "Alternate chicken cooking methods" in the blog post.