Add Pot Mixture ingredients to the Instant Pot and stir to combine. Secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 25 minutes.
When the time is up, let the pressure naturally release for 10 minutes, then quick-release the remaining pressure.
Carefully remove the chicken from the pot to a cutting board. Shred the chicken and return to the pot.
In a medium bowl, add flour a little at a time to melted butter until it makes a paste. Ladle 1 cup of the hot soup broth into the paste and stir to incorporate, then pour the butter/flour mixture into the Instant Pot.
Using the display panel select CANCEL and then SAUTE . Cook and stir until thickened, then stir in the half and half.
Serve warm topped with chopped Italian parsley
*The MANUAL and PRESSURE COOK buttons are interchangeable.