Add Seasoned Chicken (with seasoned salt) and Mirepoix to Instant Pot and Saute' with olive oil for 10 minutes.
Then place all ingredient into the Instant Pot, except for the gravy mix and milk. Only fill with stock to just below your Instant Pot fill line, you may have stock in reserve with can be used to thin at the end.
Stir to combine. Cover, seal the lid, and cook on manual/high pressure for 20 minutes.
When finished, allow to vent naturally this may take 10 minutes, then use the quick release function to vent steam remaining steam.
While cooking, mix gravy mix, and milk in separate bowl, to make a roux.
Pour the roux into the Instant Pot, after venting stir everything together to combine well. If too thick you can add any remaining stock too thin to desired consistency. Serve and enjoy