In a large bowl, combine the ground chicken, breadcrumbs, Parmesan cheese, egg, minced garlic, oregano, salt, and pepper. Mix gently until all ingredients are combined.
Shape the mixture into small meatballs, about 1 inch in diameter (you should get around 18–20 meatballs).
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the meatballs and sear them for 2–3 minutes per side until browned. Remove them from the pan and set them aside.
In the same skillet, heat 2 tablespoons of olive oil over medium heat. Add the chopped onion and sauté until soft, about 3 minutes.
Stir in the minced garlic and cook for 1 minute until fragrant.
Add the orzo to the skillet and toast for 1–2 minutes, stirring frequently to coat it in the oil.
Pour in the chicken broth, thyme, red pepper flakes, and salt. Stir to combine.
Return the seared meatballs to the pan, nestling them into the orzo mixture. Cover and simmer on low heat for 10–12 minutes, or until the orzo is tender and the meatballs are cooked through.
Stir in the spinach and cook for an additional 2 minutes until wilted.
Squeeze fresh lemon juice over the dish and sprinkle with Parmesan before serving.