In a large bowl, whisk together the ranch dressing, chopped rosemary, lemon juice, Worcestershire sauce, salt, and pepper until well combined.
Add the cubed chicken to the marinade and toss to ensure even coating.
Cover the bowl and refrigerate to marinate for at least 30 minutes.
Preheat the grill to medium-high heat (approximately 400°F / 200°C) and lightly oil the cooking grates.
If using wooden skewers, soak them in water for 20 minutes to prevent burning.
Thread the marinated chicken pieces onto the skewers, leaving a small gap between each piece to ensure even heat circulation.
Place the skewers on the grill and cook for 10-12 minutes, turning every 3-4 minutes, until the chicken reaches an internal temperature of 165°F (74°C).
Remove from the grill and allow the chicken to rest for 5 minutes before serving.