Prepare gas grill at high heat. Add rub seasoning to both sides of chicken breasts. Add chicken breasts to grill and turn heat down to medium high.

Grill for 3-6 minutes or until dark grill marks appear. Using grill-safe tongs, turn the chicken over and use a grill brush to slather bbq sauce on the chicken. After about 3-6 minutes, turn the chicken again and add bbq sauce. Turn over once again and remove chicken from the grill after 1-2 minutes. Place chicken on a plate and allow to rest for at least 5 minutes. Slice chicken into thin pieces or cut into 1 inch thick cubes.

Melt about a 1/2 stick of butter and set aside along with a brush.

Add a little bit of butter to a non-stick skillet and heat at medium. Once butter is completely melted and about to brown, 2-3 minutes, take one slice of bread and brush with melted butter. Add the bread to the pan and top with 1/4 cup of cheese, add 1/4 of the chicken and then another 1/4 cup of cheese. (Add even more cheese if you want!) Brush the second piece of bread with melted butter and add to the top of the sandwich.

Using a spatula, smash the sandwich down ever so slightly. Paying attention to the cheese (you want the cheese to melt) and the bread (don't let it burn), flip the sandwich over after about 2-4 minutes or when the bottom piece of bread is golden or dark brown. Again, using the spatula, smash the sandwich down a little. Remove from skillet after 3-5 minutes. Place on a plate lined with a paper towel so the bread doesn't get soggy. Repeat to make other sandwiches.