How to cook cooked chicken from the refrigerator?

You can reheat it in a microwave oven, in a toaster oven, or in a regular oven. Cooking time will vary, depending on the weight and thickness of pieces, and whether the chicken is frozen or just chilled in the refrigerator. A single leg or thigh might take one or two minutes to reheat in a microwave oven, depending on how powerful the oven is. One piece or many pieces can be reheated in 15 to 20 minutes on a cookie sheet or in a pan in a regular oven at 325°F.