Start by making tiny slits down each chicken breast, about 1/4" from the bottom. Season with some salt and pepper, then insert the thinly sliced pieces of the mozzarella cheese.
Spritz a rectangular piece of foil with oil, add a variety of veggies and a pinch of salt and pepper.
Place the chicken on top. Smear with the pizza sauce, olives, oregano and salt and pepper to taste.
Fold the foil over to make a book and seal it until all of the openings are closed. Repeat with the remaining three chicken breasts and place on a baking sheet.
Bake at 400 F for 20 minutes, then open up the foil (very carefully), sprinkle with the parmesan and broil for 5 minutes. Enjoy.
When opening the foil packet, I suggest carefully slicing part of it opened so the steam can release before opening it. It'll be quite hot straight from the oven and you don't want the steam to be trapped to continue (over) baking your chicken.
Change up the flavours by drizzle some bbq sauce on top as well. BBQ chicken pizza anyone?!
Make sure your chicken breasts are all the same size so that cook time is the same. Also, avoid thinly sliced chicken breasts for this as you want them to be able to hold up the sliced mozzarella.
In a similar vein, it'd be hard to make this with chicken thighs as they tend to be thinner than breasts so the cheese won't hold up in-between the slices.