Place the shredded cooked chicken in a bowl. Sprinkle the Five Spice seasoning over it and, with clean hands, massage the spices throughout the chicken for even coverage; set aside.
Heat the sesame oil in a medium-sized pot over medium-high heat. Add the garlic and ginger and simmer for about 30 seconds. Add the carrots (and if you're using shiitake mushrooms or any other vegetables that need to be cooked to tender, add them now), and simmer until tender—about 2 minutes. Decrease the heat if you feel like the garlic is browning or sticking to the pot. Additionally, you can add a splash of stock to the pot if the garlic seems to be sticking.
Once the carrots are tender, add the chicken stock to the pot. Bring it to a low simmer. Add the soy sauce, fish sauce, and sambal oelek, and let the soup simmer for about five minutes. Give it a taste and adjust as needed (add soy sauce or more heat if you need to.)
While the soup simmers, cook the noodles in a separate pot as per the package's instructions. Drain the noodles, and equally divide them into bowls.
Pour the soup over the noodles, then evenly distribute the chicken between the two bowls. Top with sliced scallions and any other toppings you've prepared—and enjoy!