Preheat the oven to 400°F. Line a baking sheet with parchment paper.
In a large bowl, combine the ground chicken, breadcrumbs, Parmesan cheese, parsley, red onion, garlic, oregano, salt, pepper, and egg. Mix until well combined.
Form the mixture into 1-inch meatballs and place them on the prepared baking sheet.
Drizzle the meatballs with olive oil and bake 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, about 8-10 minutes.
Drain the orzo and return it to the saucepan. Stir in the lemon zest, lemon juice, cherry tomatoes, and feta cheese. Mix well to combine.
Serve the meatballs over the lemon orzo, garnished with additional parsley if desired.