Peel and cut the carrots into coins
Cut each celery rib in half lengthwise and chop into pieces
Coarse chop onion
Put olive oil in Instant Pot and turn on Saute setting.
When oil is hot, add onion and cook about 1 minute stirring often.
Add remaining vegetables and cook 3-4 minutes more, stirring occasionally
Add chicken stock to Instant Pot
Add parsley, thyme, and oregano and stir well.
Trim excess fat from chicken thighs and add to Instant Pot
Add about 2 cups of the water to the pot. Don't exceed the 2/3 fill mark.
Turn off the Saute mode and secure the lid. Use the Manual setting to cook under pressure for 20 minutes.
Quick vent the steam. When the lid unlocks, remove it and resume Saute mode.
Add the remaining water to the pot
Remove the chicken from the pot. Discard the skin. Remove the chicken from the bone with a fork.
Add chicken to pot
Once the pot is boiling, add the noodles and set a timer for 7-9 minutes (per instructions on package)