Season both sides of the chicken with Montreal Steak seasoning. Cover and refrigerate for 1 hour.
In a 1-cup measuring cup, combine pineapple juice, butter, mustard, honey, molasses, Worcestershire sauce, and chili powder. Reserve 1 1/2 Tbsp. and place in a 1/4 cup.
Preheat grill to medium-high heat, 350℉. Spray chicken, both sides, with cooking spray to keep it from sticking.
Place chicken on grill and brush with sauce, cook for 5 minutes. Flip chicken and brush with sauce, cooking for another 5 minutes or until the internal temperature reaches 165℉.
Place pineapple rings on the grill and cook for 1 minute, flip, and cook another minute.
Place a slice of ham, then a slice of cheese, and lastly the pineapple ring on each breast. Drizzle with 1 1/2 Tbsp of reserved sauce. Cook until the cheese is melted.