In a large mixing bowl, combine the ground chicken, breadcrumbs, grated Parmesan cheese, minced garlic, chopped onion, parsley, mint, oregano, lemon juice, salt, and pepper.
Mix the ingredients thoroughly with your hands or a wooden spoon until well combined.
Preheat a skillet over medium heat and add a drizzle of olive oil.
While the skillet is heating, shape the chicken mixture into meatballs, about 1 inch in diameter.
Once the oil is hot, place the meatballs in the skillet, making sure not to overcrowd them. Cook in batches if necessary.
Sear the meatballs for about 3-4 minutes on each side, or until they are golden brown and fully cooked through (internal temperature should reach 165°F).
Remove the meatballs from the skillet and let them rest on a plate lined with paper towels to absorb excess oil.
Serve the Greek chicken meatballs warm with a side of tzatziki sauce for dipping.