Heat the olive oil in a medium sauce pan over medium heat. Add the rice and stir to coat. Toast the rice, stirring often, just until it starts to turn golden. Pour in the chicken broth, bring to a boil, turn heat to low, and cover. Cook, covered, for 15 - 20 minutes or until most of the liquid is absorbed. Remove from the heat and add the butter, grated zucchini, cheddar, and garlic powder. Stir until well incorporated. Cover and let sit for 5 minutes. Stir again and add salt and pepper to taste and a splash of milk if you'd like to thin out the texture a little bit.