Meanwhile, place 1 chicken breast on work surface. Notice it has a thick end and a thin end. To create a pocket for the stuffing, insert long, thin knife (a boning knife is ideal) into middle of thick end, parallel to work surface. Slide knife in until it reaches middle of chicken. Move knife up and down within the chicken to form a pocket. You want to have a smaller opening where knife entered the chicken and a larger pocket within the chicken to stuff with couscous mixture. Repeat with remaining chicken breasts.