In a large bowl, combine ground chicken, breadcrumbs, grated Parmesan cheese, egg, minced garlic, chopped parsley, chopped onion, salt, black pepper, dried oregano, and crushed red pepper flakes. Mix well until all ingredients are evenly incorporated.
Shape the mixture into 1 1/2-inch meatballs, about 16 meatballs in total.
Place the meatballs on a baking sheet lined with parchment paper, making sure they do not touch each other.
Freeze the meatballs on the baking sheet for 1 to 2 hours until solid.
Transfer the frozen meatballs to a freezer-safe airtight container or resealable freezer bag. Label with the date and freeze for up to 3 months.
To cook from frozen, heat olive oil in a large skillet over medium heat.
Add frozen meatballs to the skillet and cook for 10 minutes, turning occasionally to brown all sides.
Reduce heat to medium-low, cover, and cook for an additional 8 to 10 minutes or until meatballs are cooked through and reach an internal temperature of 165°F (74°C).
Serve immediately with your favorite sauce or side dish.