Soak the noodles in large bowl of warm water for 30-45 minutes. Set aside while you prepare the pho broth.
Add the oil to your Instant Pot and select the sautee option. One hot, add onion cutside down, and ginger. Cook, without stirring, for about 4 minutes, until slightly charred.
Add cardamom, cinnamon stick, coriander, star anise and cloves and cook for 1 minute longer, until fragrant. Add the water to the pot along with apple, cilantro, chicken, fish sauce, and sugar. Secure the lid.
Select Manual and cook at high pressure for 15 minutes.
When done, turn off the Instant Pot and let the pressure decrease naturally for 10 minutes. Set a timer and if the pressure hasn’t completely released when it goes off, turn the valve at the top to release any remaining pressure.
Remove chicken from the pot and set aside. Strain the broth and season with salt and pepper, to taste. Skim some of the fat from the broth.
When the chicken is cool enough to handle, separate the meat from the bones and divide the meat among 4 large soup bowls. (Reserve the bones for making bone broth.) Strain the noodles and divide them among the 4 bowls. Top each of the bowls with the broth and your desired toppings.