Line a baking sheet with foil and place bacon on top. Bake at 400 degrees for 15-20 minutes until crisp.
While bacon cooks. Pound chicken until all the same thickness (about 1/4 inch thick). Season with Montreal steak seasoning.
Add oil to a skillet, and brown chicken for about 4 minutes per side. Remove from an and set aside.
Once the bacon is done, cool and crumble. In the same skillet that you cooked the chicken, add a little of the bacon grease from the sheet pan and cook mushrooms until tender. Remove from skillet.
Return chicken back to the skillet. Spread 1 Tbsp of barbecue sauce over each chicken breast. Then top each with mushrooms, crumbled bacon, and a slice of cheese. Cover and cook for10-15 minutes until juices run clear and cheese is melted.
While the chicken cooks, combine all of the ingredients for the honey mustard sauce together in a bowl.
To serve chicken, top with tomatoes and green onion and honey mustard sauce on the side. Serves 4.