Rinse the quinoa under cold water and drain well. Bring broth and quinoa to a boil in a small saucepan. Lower the heat and simmer, covered, for 15 minutes. Remove from heat and let stand for 5 minutes. Fluff with a fork.
Season the chicken with garlic powder, salt, and pepper. Place on the other half of the prepared baking sheet. Bake for 15 minutes or until chicken is cooked through. Transfer the chicken to a cutting board and cut into slices.