In a large bowl, combine ground chicken, breadcrumbs, feta cheese, tzatziki sauce, parsley, minced garlic, oregano, lemon zest, salt, and pepper.
Mix everything together until well combined. Avoid overmixing to keep the meatballs tender.
Preheat a large skillet over medium heat and add the olive oil.
While the skillet heats, shape the chicken mixture into 1-inch meatballs.
Once the skillet is hot, place the meatballs in the skillet, making sure not to overcrowd them. Cook in batches if necessary.
Sear the meatballs for about 5-7 minutes, turning occasionally, until they are golden brown on all sides.
Reduce the heat to low, cover the skillet, and let the meatballs cook through for an additional 5-10 minutes until fully cooked (the internal temperature should reach 165°F).
Remove the meatballs from the skillet and let them rest for a couple of minutes before serving.
Serve the meatballs drizzled with additional tzatziki sauce and garnish with extra parsley if desired.
Notes
Avoid overmixing the meatball mixture to keep them tender.