Heat the olive oil in a pan and add the chicken strips and oregano. Cook the chicken thoroughly, and then set aside.
Put the pine nuts/walnuts and the garlic into the food processor or blender until finely minced. Add the olive oil and pulse several times. Add in the basil, yoghurt, and salt. Pulse until thoroughly mixed.
Lay the lettuce leaf flat on a plate. Spread the whole of the leaf with the dressing and then assemble your chicken and tomato slices. Wrap, secure with a toothpick and serve.