Place chicken into your slow cooker. In a glass measuring cup or medium bowl, stir together the barbecue sauce, Italian dressing, brown sugar and Worcestershire sauce.
Pour sauce over chicken breast. Turning breasts over a few times, making sure to coat chicken.
Cook on low for 4 1/2 hours.
Once the chicken is on warm, remove the chicken to a cutting board. In a small bowl mix together the water and cornstarch; mixing well.
Pour the cornstarch mixture into the slow cooker, mixing well. Cover and cook on high for about 10 minutes, until the sauce has thickened and heated through.
Meanwhile, shred the chicken. You can use your hands or I like to use two forks to shred chicken.
Return the chicken to the slow cooker and mix together. If you feel like you need any more additional barbecue sauce, then this is the time to add it.
Cover and cook on low for 45 minutes.
Pile some BBQ chicken onto rolls and Enjoy!