Set Instant Pot to Saute. Add olive oil and saute onions until softened, about 3 minutes. Add garlic, carrots, celery and thyme (if using) and saute for another minute or so.
Be sure giblets are removed, then add whole chicken to Instant Pot. Add water, soy sauce, 2 teaspoons salt and several turns of freshly ground pepper (or about 1/2 teaspoon). Turn off Saute function and set to cook at High Pressure in manual mode for 20 minutes. Cook time will start once pot is pressurized, which may take around 15 mins or so.
When cook time is finished, turn pressure valve to do quick release. If spurting liquid, wait 5 minutes then try releasing pressure again.
Carefully, remove whole chicken and set aside to shred. It will be tender and falling apart, so you may need to check broth for pieces.
Set Instant Pot back to Saute and let chicken broth come to a boil. Stir in egg noodles and cook for about 5 minutes, until tender.
While noodles are cooking, shred chicken into bite-size pieces, discarding bones and skin. Stir shredded chicken meat and fresh parsley into broth. Salt and pepper to taste. Serve warm.
Notes
Sub boneless skinless chicken breast: Use about 2 pounds raw chicken breast and 8 cups chicken broth in place of the whole chicken and water.