Set the Instant Pot to Saute and let it heat up. When the Instant Pot is hot (it won't take very long to heat up) add butter (1 tbsp) and let it melt.
Add onions to the melted butter and cook for 2 - 3 minutes, until onions are translucent.
Add the spices. Add dried thyme (1 tsp), dried parsley (1 tsp), kosher salt (1 ½ tsp), turmeric (½ tsp), chicken bouillon (1 tsp), garlic powder (1 tsp), onion powder (1 tsp), and black pepper (1 tsp), then stir.
"Deglaze" the pot with the chicken broth, then add uncooked egg noodles.
Pour frozen vegetables over the top - stirring is optional. Make sure the noodles are submerged in the broth but the vegetables don't have to be.
Lay the chicken over the noodles and sprinkle a little salt and pepper over it for extra seasoning. (I sometimes also like to add thin slices of butter on top of the chicken. As the Instant Pot heats up, the butter melts into the chicken.)
Close the lid of the Instant Pot and set the vent to Sealing.
Press the Cancel button to cancel the Saute function, then set the Instant Pot to Manual Mode or Pressure Cook at High Pressure for 7 minutes.
When the cooking cycle is complete, Naturally Release (NR) the pressure for 3 - 5 minutes by letting the Instant Pot sit and release pressure on its own. (Longer will result in softer noodles.)
After 3 - 5 minutes of Natural Release, manually release the remaining pressure. Do this carefully using a controlled release. (See below for how to do that.)
When all the pressure has been released, open the lid and remove the chicken. Place it off to the side and let it rest for a few minutes, then shred or dice it. Leave it off to the side (out of the broth) while you add the heavy cream.
Add the heavy cream to the Instant Pot and stir. Let it sit for a few minutes, then add the chicken back.
After adding the chicken back to the Instant Pot, optionally add a slurry to thicken the soup. I like to use arrowroot dissolved in water but you can also use corn starch. (This is optional as the soup will thicken as it sits but it does help thicken it faster.)
Serve while hot - seasoning with extra salt and pepper as needed. Refrigerate leftovers once cooled for up to a week. Reheat in the microwave or on the stove over low heat.