Coat the inner pot of the Instant Pot with oil. Combine apple and next 6 ingredients (oats through coconut milk) in inner pot.
Close and lock the lid of the Instant Pot. Turn the steam release handle to “Venting” position. Press [Slow Cook], and use [Adjust] to select “Less” mode. Press [-] or [+] to choose 6 hours cook time.
Stir well before serving. Garnish with toasted cashews and additional diced apple, if desired. Enjoy!