On Instant Pot™, select SAUTE; adjust to normal. Melt butter in insert. Rub chicken all over with seasoned salt, and place in insert, breast side down; sear 4 to 6 minutes or until browned. Turn and sear on back side 2 to 4 minutes longer; using tongs, transfer to plate. Select CANCEL.
Carefully place rack in insert. Add broth. Place chicken breast side up on rack. Secure lid; set pressure valve to SEALING. Select MANUAL; cook on high pressure 20 minutes. Select CANCEL. Keep pressure valve in SEALING position to release pressure naturally. Internal temperature in thigh should be at least 165°F using instant-read thermometer. If chicken is not done, select MANUAL and cook on high pressure 2 to 5 minutes longer. Select CANCEL. Keep pressure valve in SEALING position to release pressure naturally.
When cool enough to handle, carefully transfer chicken to cutting board, and remove rack.
Select SAUTE, and adjust to normal; heat liquid to simmering. In small bowl, beat cornstarch and water with whisk; stir into liquid and cook 1 to 2 minutes, stirring constantly, until thickened.