Boil the ramen noodles according to package instructions, then drain and set aside.
Heat vegetable oil in a large pan over medium heat.
Add minced garlic and sauté for 30 seconds until fragrant.
Stir in soy sauce, oyster sauce, sesame oil, and red pepper flakes.
Add the cooked ramen noodles and toss to coat evenly.
Mix in chopped green onions and sesame seeds.
If using, add cooked chicken and stir for another minute.
Serve hot and enjoy!