Preparation:

Preheat Oven: Set your oven to 350°F (175°C). This temperature is ideal for warming the chicken without drying it out.

Remove from packaging: Take the roasted chicken out of the packaging and let it sit at room temperature for about 10-15 minutes. This step helps the chicken reheat evenly. 

Reheating:

Wrap in Foil: To prevent the chicken from drying out, wrap it loosely in aluminum foil. This helps retain moisture and ensures even heating.

Place in Oven: Set the wrapped chicken on a baking sheet or in a baking dish, and place it in the preheated oven.

Heat Thoroughly: Reheat the chicken for about 20-25 minutes. The exact time may vary depending on the size and cut of the chicken. For a whole chicken, it might take a bit longer.

Check Temperature: Use a meat thermometer to check the internal temperature of the chicken. It should reach at least 165°F (74°C) to ensure it's heated through.

Rest Before Serving: Once heated, let the chicken rest for a few minutes before unwrapping. This allows the juices to redistribute, ensuring a moist and flavorful chicken.

Microwave Alternative:

If you're short on time, you can use a microwave. Place the chicken on a microwave-safe dish, cover it with a microwave-safe lid or wrap, and heat on medium power in 2-minute intervals, checking the temperature in between, until it reaches 165°F (74°C).

Note: Reheating times can vary based on individual ovens and microwave wattages. Adjust accordingly and always ensure the chicken is thoroughly heated before serving.