MEATBALLS: In a large bowl, mix together ground chicken, minced garlic, egg, Parmesan cheese, parsley, and red pepper flakes; season with salt and pepper. Using a cookie scoop form into tablespoon-sized meatballs.
In a large skillet heat olive oil over medium heat. Cook meatballs until golden on all sides and cooked through, about 10 minutes. Transfer to a pie plate and loosely cover with foil.
PESTO SPAGHETTI: Meanwhile, boil pasta in a large pot of salted water according to package directions for al dente. Reserve 1 cup pasta water and drain spaghetti.
Add drained pasta to the skillet with pesto, toss to coat. Add enough water to moisten. Gently stir in meatballs; cook until heated through.