1 rotisserie chicken

1 white onion, halved
1 teaspoon whole coriander
1/2 teaspoon whole cloves
1/2 teaspoon black peppercorns
1 cinnamon stick
6 cardamom pods
12 cups chicken broth
2 tablespoons fish sauce
1 tablespoon brown sugar
1-pound fresh rice stick noodles
Chopped green onions, bean sprouts, mint, cilantro and basil, for garnish.
Sriracha for serving, if desired
Remove meat from chicken and shred. Reserve bones and skin. In a stockpot over medium heat, sear onion cut side down until browned, about 3 minutes. Add spices and toast until fragrant, about 2 minutes. Add chicken bones and skin, then add stock. Simmer for 1 hour. Stir in fish sauce and sugar. Strain stock and return to heat. Stir in shredded chicken.
In a saucepan, boil noodles just until tender, about 20 seconds, stirring to break them up. Drain.
To serve, place a handful of noodles in a bowl. Spoon broth over and top with green onions, bean sprouts and herbs. Season with sriracha if desired.