Place chicken thighs on cutting board, large plate, or flat surface covered with parchment paper.
Add salt, pepper, and garlic powder to small bowl. Mix spices together, then sprinkle mixture on chicken thighs, covering thighs evenly. Flip chicken thighs over and repeat seasoning process. Set chicken thighs aside.
Set Instant Pot to Sauté mode. Add neutral oil and stir oil slightly to distribute across bottom of Instant Pot insert.
When oil is hot and shimmery, place chicken thighs in Instant Pot, skin-side down. Sear chicken thighs 4 to 5 minutes or until skin is browned and releases easily from pot.
Flip thighs over and sear other sides 3 minutes or until meat is just no longer pink. Transfer chicken thighs to plate and set aside.
Pour chicken broth (or water) into Instant Pot to deglaze insert. Use large wooden spoon to scrape up any browned bits of chicken that may be stuck to bottom of insert.
Place trivet in Instant Pot. Layer chicken thighs on top of trivet, then secure lid on Instant Pot with vent in Sealing position.
For Bone-in Thighs: Set Instant Pot to Manual High Pressure for 9 minutes. Instant Pot will pressurize, then 9-minute cook time will begin.
For Boneless Thighs: Set Instant Pot to Manual High Pressure for 8 minutes. Instant Pot will pressurize, then 8-minute cook time will begin.
Once cook time is up, Natural Release pressure for 5 minutes. After 5 minutes, immediately Quick Release any remaining pressure.
Carefully remove lid and transfer chicken thighs to cutting board or platter. Allow chicken thighs to rest 5 minutes before serving.