In a small bowl, combine the dried oregano, paprika, garlic powder, onion powder, salt and pepper. Rub the spice mixture over all sides of the chicken thighs, trying to get some under the skin if using skin-on thighs.

Pour the olive oil into the Instant Pot inner pot and press the "Sauté" button to turn on sauté mode. Once the oil is hot, spread it over the bottom of the pot. Carefully place the seasoned chicken thighs in the pot, skin side down. Cook about 4 minutes per side, until both sides are browned. Remove chicken to a clean plate.

Turn off the Instant Pot and pour the chicken broth into the inner pot. Use a spatula to scrape up any browned bits on the bottom of the pot. This will ensure that you do not get a burn warning during the pressure cooking process.

Place the metal trivet in the Instant Pot. Put the chicken thighs on top of the trivet, skin side up.

Close the Instant Pot lid and turn the steam release valve to the sealing position.

Pressure cook at high pressure:Bone-In Thighs: Cook at high pressure for 10 minutes. The Instant Pot will take about 5 minutes to reach pressure and then the cook time will begin counting down. When the cook time has finished, allow the pressure to release naturally for 5 minutes (just leave the Instant Pot alone).Boneless, Skinless Thighs: Cook at high pressure for 8 minutes. The Instant Pot will take about 5 minutes to reach pressure and then the cook time will begin counting down. When the cook time has finished, allow the pressure to release naturally for 5 minutes (just leave the Instant Pot alone).Frozen Thighs: See note below.

Then carefully turn the steam release valve to the venting position to release any remaining pressure. When the float valve drops down carefully open the Instant Pot lid. Use an instant-read thermometer to check that the internal temperature of the chicken has reached 165° F. (If not done, you can turn on sauté to bring the broth to a boil, then turn off the pot and put the lid back on for a few minutes to finish cooking the thighs from the residual heat.)

Remove chicken and trivet from pot. If desired, pour the liquid from the pot through a strainer to strain out any solids and then return the liquid to the pot. Turn on sauté. Add the butter to the broth in the pot.

In a small bowl, stir together the 1 ½ tablespoons each of cornstarch and water. Stir this cornstarch slurry into the liquid in the pot. Bring to a boil and cook at a simmer, stirring occasionally, until the gravy thickens. Remove from the heat and serve with the chicken.