In a large pot, combine the chicken, onion, ginger, and water. Bring to a boil, then reduce to a simmer.
Add cinnamon, star anise, cloves, and coriander seeds. Simmer for 1.5 to 2 hours, skimming any foam.
Remove the chicken and let it cool slightly. Shred the meat and set aside.
Strain the broth to remove solids, then return it to the pot. Add fish sauce and season with salt.
Cook rice noodles according to package instructions. Divide into bowls.
Top noodles with shredded chicken and ladle hot broth over. Garnish with herbs, lime wedges, and bean sprouts.
Serve with sriracha or chili sauce for added spice.