Make the chicken broth: In an Instant Pot, add the chicken broth ingredients and pressure cook on high for 30 minutes.
Make the meatball mixture: In a mixing bowl, combine all the meatball ingredients except for the meatloaf mix. Once everything is mixed well, add in the ground meat and mix. This will prevent the meat from being overmixed and tough.
Form the meatballs: Form 1 inch meatballs and place on a baking sheet lined with parchment paper. Refrigerate the meatballs.
Strain the chicken broth: Quick release the Instant Pot then place a fine mesh strainer over a large bowl and strain the broth.
Make the soup: In the same pot, set the Instant Pot to sauté high and add the olive oil. Sauté the onion, celery, and carrots for 5 minutes. Add the chicken broth back in and bring to a boil then simmer for 10 minutes. Add in the meatballs and bring it back to a boil then simmer for 10 minutes. Turn off the Instant Pot and stir in the escarole, chicken, and cheese. Let it sit for 10 minutes to let the residual heat cook the escarole.
Notes
I made about 86 meatballs.
Make the soup a day ahead of time to allow the flavors to meld. This will also solidify any excess fat on top which will be easier to remove.
Mix the ingredients for the meatballs first, then mix in the meat. Overworking the meat will result in a tough meatball.