This is a remake of a food I found in the frozen section of the store (chicken melt), just waiting to be reheated.
These were remarkably simple. A pita or flatbread for the outside with some slightly spicy chicken and cheese on the inside. Good for on the go, or sliced up to be used as appetizers. The ones from the store were slightly dry so I recommend either giving it a light spritz with water before cooking it, or pairing it with a sauce to dip into.
Simply precook the chicken, and put it in a tortilla with cheese, then you can microwave it or put it in the oven to melt if you plan to have it right away or cold afterwards. If not, store it with the cheese un-melted and you can just microwave it and eat it when ready. Sliced cheese (unmelted) is much better for storing than shredded.
To get a nice shape for the chicken, you can either cut it in half height-wise or pound it out with a meat mallet. Having it thinner makes it better for cooking through without overcooking it or undercooking it while broiling. It is also easier to get it into the shape you want it to fit your tortilla or anything else you would substitute.
You can use any cheese you want really, slices or shredded too. Both the type and amount will change how well it melts however, so if you want it super melty, use cheeses accordingly.