Preheat an indoor grill on your stove top. (See note)
Flatten your chicken by pounding it with a meat hammer or a rolling pin. Rub both sides of the chicken breasts with taco seasoning. Spray the grill with cooking spray (Skip this step if using an outdoor grill). Grill the chicken for about four minutes on each side or until the inside reads 165 on an instant read thermometer.
Remove chicken from the grill, slice and divide the chicken and the remainder of the ingredients into four equal parts. Serve immediately or store in the refrigerator for up to three days.
An alternative to grilling the chicken indoors (or outdoors) is baking it. You won't get the seared taco taste, but it's still delicious)