Begin by drying the boneless, skinless chicken thighs with paper towels. Rub the chicken with the BBQ rub, ensuring an even coating. Preheat your grill to medium-high heat and grill the thighs for 5–6 minutes per side, or until the internal temperature reaches 165°F and the outside is nicely browned. Once cooked, let them rest for a few minutes before chopping.

While the chicken rests, preheat your oven to 400°F. Slice the sub rolls in half and place them on a baking sheet. Toast the rolls in the oven for 3–5 minutes, or until they are lightly golden and slightly crispy.

On a cutting board, gather your grilled chicken, thick-cut bacon, and fresh tomatoes. Chop the chicken and bacon into bite-sized pieces, keeping them chunky for a satisfying bite. Dice the tomatoes and prepare the shredded lettuce.

In a large mixing bowl, add the chopped chicken, bacon, tomatoes, and shredded lettuce. Sprinkle in salt, pepper, and mozzarella cheese, then drizzle the ranch dressing over the top. Gently toss these ingredients together until everything is well coated.

Load the generous mixture into each toasted roll, evenly distributing the filling among them. Press down slightly to ensure the ingredients stay in place. Serve immediately while warm.