Preheat the oven to 350 degrees F.
Place the chicken on a baking sheet. Season with salt,garlic powder and pepper. Bake the chicken for 35 to 40 minutes, until the skin is lightly browned and the chicken is just cooked through. Set aside until cool enough to handle, then remove the meat from the bones and discard the skin and bones. Cut the chicken into large dice and set aside.
Cook the potatoes in a large pot of boiling salted water for 10 minutes, and drain. When the potatoes are cool enough to handle, dice them into 1/4-inch cubes.
Heat 4 tablespoons of oil in a large saute pan, over medium-low heat. Working in batches, add the potatoes in a single layer and fry them for 5 to 7 minutes, until evenly browned and cooked through. Remove from pan,add additional 2 tablespoons oil,add the onions and cook over medium-low heat for 5 to 7 minutes, .
Add the chicken and potatoes. Turn heat to medium high,mashing down mixture without stirring to lightly brown the bottom. Serve with gravy.