Cut the spinach into very thin strips (chiffonade). Divide among 4 shallow soup or pasta bowls and top with the dill. Set aside. In a saucepan, heat the chicken broth over medium heat and add the lemon juice and zest and the chicken. Cover and poach for 2 to 3 mintues, until the chicken is white and cooked through. Remove the chicken with a slotted spoon and divide evenly among the bowls. Ladle the broth over the chicken and season with pepper. Top with the Parmesan shards and nutmeg and serve immediately.