How to Make It
Combine first 11 ingredients (through bay leaf) in a 6-quart Instant Pot®. Close and lock the lid of the Instant Pot®. Turn the steam release handle to "Sealing" position. Press [Manual]; select "High Pressure," and use [-] or [+] to choose 19 minutes pressure cooking time. When time is up, turn cooker off. Open the cooker using Natural Pressure Release (page 4). Remove and discard bay leaf.
Add chicken to cooker. Press [Sauté], and use [Adjust] to select "More" mode. Cook, uncovered, 3 minutes or until thoroughly heated, stirring occasionally. Ladle soup into 6 bowls. Sprinkle with additional oregano and pepper, if desired.