12 hours before: make cuts into the chicken breast, and massage it with salt, pepper, oil and seasonings (laurel, thyme, oregano, rosemary, as you like), wrap it into shrink wrap, and leave in the refrigerator to marinate.
Unwrap the chicken breast, and boil it or steam it (it should be cooked but still tender). Once ready, let it cool down.
Prepare the green sauce: mix together cappers (previously desalted), olives, parsley, basil, oil and vinegar. Adjust with salt at the end, and add oil or vinegar if needed, in order to obtain a creamy green sauce.
Wash, dry and cut the lettuce in slices, put it on a plate. Rip up the meat with your fingers on the lettuce and season with the green sauce. Serve warm or at room temperature.