Heat the oil in a large pot over medium-low heat. Add the onion and ginger and sauté until the onion is translucent, about 5 minutes. Add the broth, fish sauce and sugar. Place the star anise and cloves in a tea ball or wrap in cheesecloth and add to the pot. Add the chicken. Bring to a boil. Reduce the heat and simmer until the chicken is cooked through, about 15-20 minutes. Using tongues, transfer the chicken to a plate. Simmer the broth about 10 minutes longer to develop the flavors.
Meanwhile, place the noodles in a bowl or glass baking dish. Cover with very hot water and let soak at least 3 minutes to soften. Prepare the garnishes.
Add bok choy to the soup and simmer just until the bok choy begins to wilt, about 3 minutes. Add the spinach and snow peas, if using, and simmer just until the spinach wilts, about 1 minute. Season the soup to taste with salt and generously with black pepper. Ladle into bowls.
Serve, allowing diners to add hoisin, chili sauce, green onions, cilantro, chilies, bean sprouts, basil and lime to taste.