Place chicken breasts on a flat sheet.
Sprinkle over breasts, the garlic Cajun spice, lemon juice and chives.
Rub ingredients over each breast making sure to cover as best as possible.
Once BBQ is hot, place smoker box with water soaked wood chips directly on the burner grate, placing it to the back or front, or side to side depending on how the burners are set up on your BBQ. If you don't have a smoker box you can toss larger chips that have been soaked in water directly on the coals. The reason you placed the smoker box to one side is that you are going to cook the chicken indirectly, so turn off the burner that is opposite to the smoker box side.
Cook for about 30 minutes, without flipping the breasts.