Place 6 chicken breasts in the bottom of a crock pot.
Sprinkle the chicken with 1 teaspoon black pepper and 1 teaspoon garlic salt, then pour ¾ cup barbecue sauce (half of the 1½ cups total) and 1 cup Coca-Cola (from the 12 ounces) over the top.
Cover and cook on low for 5–6 hours or on high for 3 hours.
Drain the liquid from the crock pot, leaving the chicken in the crock pot.
In a small mixing bowl, whisk together the remaining ¾ cup barbecue sauce and the remaining Coca-Cola.
Pour the mixture over the chicken.
Cover and cook on low for 1 more hour.
Serve the chicken whole topped with the sauce, or shred the chicken and stir it back into the sauce.
Video
Notes
Refrigerate the leftovers in an airtight container for up to 5 days.