In a large saucepan, bring the broth to a boil. Add the pasta and boil until tender, 8 to 9 minutes.
In a large bowl, beat the egg yolks. Gradually whisk in 1 cup of the hot broth. Add the egg mixture to the saucepan, reduce heat to medium, and cook, stirring, until thickened, 5 to 7 minutes.
Add the chicken and lemon juice to the saucepan. Season with ½ teaspoon salt and ¼ teaspoon pepper.