Preheat oven to 475. Season chicken with salt, pepper and garlic salt. Heat oil in a heavy nonstick skillet over high heat until hot but not smoking. Place chicken in skillet, skin side down, and cook 2 minutes. Reduce heat to medium-high and continue cooking skin-side down, occasionally rearranging chicken and rotating pan to evenly distribute heat, until fat renders and skin is golden brown - about 12 minutes. Transfer skillet to oven and continue cooking 13 more minutes. Flip chicken and continue cooking until skin crisps and meat is cooked through - about 5 more minutes. Transfer to a plate and let rest 5 minutes before serving.