Using a wok or deep skillet either spray with cooking spray or add the olive oil. Place chicken breasts in bottom of pan & sprinkle with pepper if desired. If using peppered bacon, eliminate the pepper as it can become overly peppered. Brown chicken for 4-5 min. on each side. Remove the chicken from the pan & place to the side while preparing the remaining ingredients. (I place it in a warming dish on the stove so it did not cool too much)
Leaving the drippings from the chicken in the wok/skillet, fry the bacon to desired crispness, remove & place bacon on paper towel to strain the remaining grease. Lightly saute' the onions & mushrooms in the pan drippings for about 5 min. Chop the bacon into chunks while the mushrooms & onions saute'.
Turn heat to medium & Replace Chicken breasts in bottom of pan and cover with the mushroom mixture, & sprinkle the bacon & top with the shredded Swiss. You will not use all the bacon, I freeze the rest so I can use it in additional baking & cooking for flavor. Cover the pan with a lid, while you make the remaining side dishes. Once the cheese is completely melted turn heat to low until ready to serve.