To prepare the tagliatelle with slivers of chicken in a creamy green peppercorn sauce, you will need: 1 pound chicken breasts, 2 tablespoons olive oil, 1 teaspoon kosher salt, and 2 teaspoons freshly ground black pepper. Cook the chicken until it reaches an internal temperature of 165?F (77?C) and then remove it from the heat. Add the remaining ingredients and stir to combine. Set aside.