Add in the cilantro and cook another 5 minutes. Remove from heat. To finish, add in the remaining 2 Tbsp of butter and stir until melted.
Coat medium sized oven proof casserole dish with olive oil or non-stick spray. Add the cooked sliced chicken to bottom, then spoon gravy over it. Top with shredded cheese.
Put casserole dish in oven and heat at 400F for about 15 minutes until chicken is warmed and cheese is melted.