In a large pot, combine 8 cups of chicken broth, the halved onion, ginger slices, star anise pods, and the cinnamon stick. Bring to a boil over medium-high heat, stirring occasionally.

Reduce heat to low and let broth simmer for 15-20 minutes. Add fish sauce, soy sauce, and sugar to enhance flavor.

In another pot, boil water to cook the rice noodles according to package instructions, about 5-7 minutes. Drain and rinse with cold water.

Shred the rotisserie chicken into bite-sized pieces, discarding skin and bones, about 5 minutes.

In serving bowls, place a portion of the cooked rice noodles and warm shredded chicken on top.

Carefully strain the broth to remove the solids. Ladle the hot broth generously over the noodles and chicken.

Garnish with fresh herbs, lime wedges, jalapeños, and bean sprouts as desired.

Serve hoisin and sriracha sauces on the side for customization.