Marinate the Chicken
Slice each chicken breast in half lengthwise to create four thinner pieces.
In a large bowl, whisk together pickle juice, milk, powdered sugar, garlic powder, onion powder, black pepper, salt, and smoked paprika.
Submerge the chicken in the marinade, cover, and refrigerate for at least 30 minutes (or up to 4 hours for maximum flavor).
Prepare the Honey Roasted BBQ Sauce
In a bowl, whisk together mayonnaise, BBQ sauce, honey, Dijon mustard, lemon juice, and smoked paprika.
Cover and refrigerate until ready to use.
Grill the Chicken
Preheat your grill or grill pan to medium heat.
Remove the chicken from the marinade and grill for 6-8 minutes per side, or until fully cooked (internal temperature of 165°F/74°C).
In the last minute of cooking, place a slice of cheese on each piece of chicken to melt slightly.
Toast the Buns
Lightly butter the insides of the multigrain buns and toast them on the grill or in a skillet until golden brown.
Assemble the Sandwiches
Spread the honey roasted BBQ sauce on the bottom half of each bun.
Layer with green leaf lettuce, a slice of tomato, and the grilled chicken breast with melted cheese.
Place a crispy bacon slice on top, then cover with the top half of the bun.
Serve and Enjoy
Serve warm with your favorite sides like waffle fries, coleslaw, or a fresh fruit salad.