Set the Instant Pot to Sauté and heat the oil until shimmering. Add the halved onion and sliced ginger and cook, turning occasionally, until they are nicely browned, about 4 minutes.
Add the whole garlic cloves, whole coriander seeds, and star anise; sauté for about 2 minutes until fragrant.
Add the chicken to the pot and pour in enough water to cover the chicken (about 2 quarts). Seal the lid and set the cooker to high pressure for 20 minutes.
While the chicken cooks, prepare the rice noodles according to package instructions and drain; chill the thinly sliced onion in cold water.
When pressure cooking finishes, carefully release the pressure and remove the lid. Transfer the chicken to a large bowl and set aside to cool slightly.
Strain the broth through a fine-mesh sieve to remove solids and spices; discard the solids and return the clear broth to the Instant Pot on Sauté/Boil to keep it hot.
Stir the fish sauce and sugar into the hot broth, taste, and adjust seasoning with more fish sauce or sugar if needed.
Remove the meat from the chicken bones and shred into bite-size pieces; discard bones and skin as desired.
Divide the cooked rice noodles and shredded chicken among bowls. Top each bowl with drained sliced onion, cilantro, basil, bean sprouts, and jalapeño slices.
Bring the broth to a full boil and ladle the hot broth over each assembled bowl. Serve with lime wedges, Sriracha, and hoisin sauce for individual seasoning.
