Turn the Instant Pot on to Saute. Heat the oil and saute the onions until softened.
Add the chicken thighs, fish sauce, and pepper. Lightly brown the chicken before adding the water.
Close the Instant Pot lid and press Soup function of Pressure Cook on High Pressure for 10 minutes.
Quick release the pressure. Remove the chicken from the Instant Pot and shred the meat with a fork. Discard the bones.
Turn on the Instant Pot to Saute. Let the soup boil and add the egg noodles and carrots. Season as needed. Allow to simmer until the noodles are cooked.
Blanch the cabbages into the soup before serving.
Place the mami into soup bowl together with the soft boiled eggs, green onions and fried garlic bits.