Season the chops all over with salt and pepper.
Select SAUTE and adjust to MORE on the Instant Pot.
Add the oil and heat until it shimmers.
Add the chops and let them cook on one side until golden brown, about 4 minutes.
Flip the chops and brown on the other side for another 4 minutes.
Transfer the chops to a plate and loosely tent with foil.
Add the onion to the Instant Pot, stirring frequently, until softened and lightly browned, about 3 minutes.
Add the mushrooms and 1/2 teaspoon salt, 1/2 teaspoon black pepper, and the thyme, and cook, stirring frequently, until the mushrooms are soft and have released liquid, about 4 minutes.
Add the wine and deglaze by scraping the bottom of the pan to release any browned bits.
Let the wine simmer until reduced by half, about 4 to 5 minutes.
In a medium bowl, whisk together the chicken stock, Worcestershire sauce, and flour.
Add to the Instant Pot and stir to combine with the onions and mushrooms.
Transfer the chops to the Instant Pot and spoon some of the onion mixture over them.
Lock the lid into place and select MEAT/STEW or PRESSURE COOK or MANUAL, and adjust the pressure to LOW and the time to 1 minute.
After cooking, naturally release the pressure for 3 minutes, then QUICK RELEASE any remaining pressure. Unlock and remove the lid.
Transfer the chops to a serving platter.
Add the sour cream to the sauce and stir to combine.
Taste and add more salt and/or pepper, if necessary.
Spoon the sauce over the chops and sprinkle the chopped chives on top.