Press the sauté button on the Instant Pot and add the butter to the pot. Once the pot is hot, add the onion, garlic, carrots and celery and cook, stirring occasionally, until veggies start to soften, about 3 minutes. Stir in the garlic.

Press "Cancel" to turn off the Instant Pot.

Add the dried oregano, thyme, salt, pepper, broth, milk and water to the pot. Stir. Nestle the chicken into the broth.

When the cook time ends, allow the Instant Pot to naturally release for 10 minutes. Then, carefully release the remaining pressure by turning the steam release valve to the venting position using the handle of a long spoon.

When the pin drops down, open the Instant Pot lid. Remove the chicken to a clean plate, bowl, or cutting board. Let the chicken rest for a few minutes and then shred the chicken.

Press "Cancel" to turn off the warm setting and then press "Saute." Add the noodles to the pot and let them simmer for about 5 minutes, until just tender. Turn the Instant Pot off.