In a large pot, simmer the stock and star anise over medium-high until the stock is infused with the star anise, about 10 minutes. Add the noodles, shredded chicken and carrot. Cook, stirring occasionally, until the noodles are al dente, about 5 minutes. Stir in the lime juice.
Divide the soup among bowls and top with the bean sprouts, mint and chiles. Serve with sriracha.