Preparation:

1. Bring a large pot of water to a boil. Add salt and noodles and cook for 5-10 minutes, or until al dente. Drain the noodles and rinse with cold water.
2. Meanwhile, chop the onion and garlic. Cut the carrot into small pieces. Remove the stems from the mushrooms and slice.
3. Heat the vegetable oil in a large skillet over medium heat. Add the onion and garlic and cook until softened, about 5 minutes.
4. Add the shredded chicken and cook until browned, about 5 minutes.
5. Add the carrot and mushrooms and cook for 2-3 minutes, or until softened.
6. Season with salt, pepper, fish sauce, and sugar to taste.
7. Add enough water to the skillet to cover the vegetables and bring to a boil. Reduce heat to low and simmer for 15-20 minutes, or until the vegetable are tender.
8. Add the cooked noodles to the soup and simmer for 2-3 minutes, or until heated through.
9. Seve the soup hot. Garnish with chopped fresh herbs, if desired.