In a small bowl, stir together the barbecue sauce and Italian dressing until combined.
Place the chicken breasts in a large bowl or resealable bag. Pour the sauce mixture over the chicken and toss to coat.
Cover or seal and marinate in the refrigerator for at least 4 hours or overnight.
Preheat the grill to medium-high heat.
Grill the chicken for 7–10 minutes per side, or until the internal temperature reaches 165°F.
Remove the chicken from the grill and let it rest for 5 minutes before slicing.
Slice and serve.
Notes
You can also bake this chicken at 400 degrees F in a 9X13 baking pan uncovered for 25-30 minutes until the chicken reaches an internal temperature of 165 degrees F.