Place the ground chicken, Italian breadcrumbs, Parmesan cheese, egg, garlic, lemon zest, parsley, salt and pepper into a mixing bowl. Use your hands to combine the mixture until everything is incorporated evenly.
Using a 2-tablespoon cookie scoop, scoop and roll the meatball mixture into 2-inch meatballs, about 16 meatballs total. If you prefer, you can use a 1-tablespoon scoop and make 32 1-inch meatballs instead.
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Sear the meatballs until they form a golden crust on all sides, about 5 to 6 minutes total (or 3 to 4 minutes if you made 1-inch meatballs). Place the meatballs on a plate and set aside. It’s okay if they aren’t fully cooked through, they will cook a little more later on when simmering in the sauce.
Using the same skillet, melt the butter and garlic over medium heat. Stir so the garlic doesn’t burn, scraping up any leftover bits from the meatballs. Add the white wine and allow it to simmer for 4 to 5 minutes, until it reduces slightly.
Add the chicken broth, lemon juice, lemon zest, capers, and optional red pepper flakes, and simmer for another 5 minutes, until the sauce begins to thicken. If you like a thicker sauce, mix together 2 teaspoons cornstarch and 2 teaspoons water and stir it into the sauce.
Place the meatballs back into the skillet and coat them in the sauce. Allow them to simmer in the sauce for 4 to 6 minutes, until cooked through and an internal temperature reaches 165°F.
Serve meatballs right away with pasta, mashed potatoes, or rice. Garnish with Parmesan cheese, chopped parsley, and lemon slices if desired.