Rub the chicken fillet with salt, pepper and olive oil, wrap in microwave cling film and bake in the oven at 140°C for 15 minutes. Cool in a film, remove it, cut the fillet into small cubes.
Pour boiling water over the peach, then cold water. Remove the skin, cut the peach in half, remove the stone, cut the flesh into 1.5 cm cubes.
With a paring knife, remove the outer layer of tough fibers from the celery stalks, cut the flesh into thin slices. Chop nuts.
Mix peaches, chicken fillet and celery, season with mayonnaise to taste, pepper, mix, put on plates, sprinkle with nuts, garnish with celery leaves and serve.