place chicken breasts in a pot on the stove. Pour the bottle of BBQ sauce over the breasts. Fill the BBQ jar ½ - ⅔ way full of water. Shake the bottom to remove extra sauce. dump into the pot.
Bring to a boil over medium-high heat. Once boiling, cover with a lid, reduce heat and simmer for 8-12 minutes. (large chicken will need 12. smaller breasts will be done at 8min)
place chicken on a cutting board and cut into little cubes about ½in-1in in size.
place a tortilla on a frying pan over medium low heat. add cheese and chicken. place tortilla on top. Cook on each side until browned and cheese is melted. about 2-3 min per side.
slice and serve with toppings of choice.