Add the cooked chicken to the Instant Pot, and top with egg noodles
Add Herbes de Provence, minced onions, sea salt, garlic powder and pepper, and pour chicken broth over and around egg noodles. Press down lightly with wooden spoon or spatula
Place lid on Instant Pot, turn vent to Sealing, and hit PRESSURE COOK for 4 minutes
Pot will take a few minutes to reach pressure, then cook for 4 minutes. When pot beeps, turn vent for a quick release
When pin drops, remove lid, and stir. There will be liquid in the pot, but this will be absorbed the egg noodles.
Stir in frozen vegetables, then stir in heavy cream. Stir in cheeses, one at a time, and mix until thick and creamy. Casserole will continue to get thick and creamier as it cools