Add all meatball ingredients to a mixing bowl. Mix well with hands until all ingredients are incorporated. Roll 1/2 tsp. amounts of meat mixture into meatballs. Set on a baking sheet. Once rolled, stick in the freezer while you prepare the other ingredients. Freeze for 10 minutes.
Add chicken broth, spinach, and orzo noodles to the Instant Pot. Stir well. Add meatballs and stir. Put on lid and turn to sealed. Turn cook time to 4 minutes on manual pressure.
Let cook for four minutes and then quick release pressure. Release pressure slowly, in short bursts, to avoid broth coming through the release valve. Remove lid and add cooked chicken and parmesan cheese. Stir well.
Slowly drizzle in egg and stir as it hits the broth. It should cook instantly. Taste and add more salt and pepper as needed. Serve immediately.