Marinade the chicken breasts with Italian dressing in the refrigerator for several hours, or overnight.
Remove the chicken from the marinade, shake off excess, then sprinkle poultry rub on both sides of each breast.
Preheat your oven to 400 degrees. Line a baking sheet with parchment paper, then lay out the bacon side by side on the paper. Cook the bacon for 10 to 20 minutes until the bacon fat is rendered, and the bacon is cooked but not overcooked. You will need to check frequently after 10 minutes because the cooking time might be slightly different in your oven.
Cook the bacon slices in the oven while you preheat the grill.
Bring the grill temperature up to 400℉ over oak or mesquite lump charcoal.
Lightly toast the ciabatta bun halves over the hot coals, then set aside.
Grill the chicken until internal temperature reaches 165℉. Add the Swiss cheese, and close the grill lid for just a minute to melt the cheese. Remove the chicken, and rest under loose foil for 5 minutes. Don't let the foil touch the melted cheese or it will come off.
Add a generous amount of Gaspard's Gold BBQ sauce to each toasted bun half.
Top the bottom bun with the chicken and cheese. Add tomato, lettuce, bacon, then the top bun - in that order.
Slice the sandwich in half and serve. Delicious!