First cut the chicken into strips (of the size you prefer), put it in a bowl, cover it with milk and let it rest for 30 mintues.
In a separate bowl, add chopped pistachios, pecorino cheese and breadcrumbs.
Drain the meat and pass it in the breading.
Heat a little oil in a non-stick pan and cook over medium-low heat until golden brown on both sides.
Pistachio chicken is ready: salt (and pepper, if you like) to taste and serve immediately.