Set the Instant Pot or pressure cooker to sauté mode. Add butter to the pot. Once butter is melted, add the chicken thighs skin side down. Cook for 3 to 4 minutes on each side until skin is golden brown. Remove chicken thighs from pot and set aside.
Add stock and lemon juice to the pot. Hit the cancel button on the pot. Add the chicken thighs back to the pot. Add the whole garlic cloves. Lock the lid and turn the valve to seal. Cook at manual pressure for 12 minutes, and allow the pot to do a full natural pressure release (mine takes about 15 minutes to depressurize). Internal temperature should be at or above 165°F. Serve with a simple side dish and enjoy!
Optional: Use an immersion blender to puree garlic cloves once chicken is cooked. Turn pot to sauté and let mixture reduce. Pour over chicken thighs for additional flavor.
*Cook time may vary slightly, based on the size of your chicken thighs.