In a large bowl, combine ground chicken, breadcrumbs, Parmesan cheese, parsley, red onion, garlic, oregano, salt, pepper, and egg. Mix until well combined.
Preheat the oven to 400°F. Line a baking sheet with parchment paper.
Form the chicken mixture into 1-inch meatballs and place them on the prepared baking sheet. Drizzle with olive oil.
Bake the meatballs for 20-25 minutes, or until cooked through and golden brown.
While the meatballs are baking, bring the chicken broth to a boil in a medium saucepan. Add the orzo and cook according to package instructions until al dente.
Drain the orzo and return it to the saucepan. Stir in lemon juice, lemon zest, and season with salt and pepper to taste.
Serve the meatballs over the lemon orzo, garnished with additional parsley if desired.