Heat the oil over medium-high heat in a large, heavy grill pan or cast iron skillet.
Pat the chicken breasts dry with a paper towel. Spray each chicken breast with the cooking oil spray. Season both sides of the chicken breasts lightly or to taste with sea salt, lemon pepper and garlic powder.
Add the chicken breasts to the grill pan or skillet and cook for 7 minutes, without moving the chicken around. (If your skillet is small, cook half the chicken breasts completely first, then cook the second batch the same way.)
Flip both chicken breasts over, and continue to cook for about 7 or 8 minutes more, or until the juices run clear when you cut the chicken. The chicken is done when internal temperature reaches 165F.
Remove the chicken breasts from the skillet, and repeat if needed with additional chicken breasts.
Let the chicken rest for about 5 minutes before serving. If you're storing the chicken to use at a later time, place it in a covered container in the refrigerator where it will keep for 3 to 4 days.
