Add the frozen meatballs to the Instant Pot, then add the pineapple chunks, water, soy sauce, ketchup, brown sugar and onions. Do not stir
Place lid on pressure cooker, make sure valve is at sealing position, and hit PRESSURE COOK for 5 minutes
Pot will take a few minutes to pressurize, then count down and cook. When pot beeps, quick release pressure
When pin drops, carefully open lid, and stir. Hit CANCEL, then hit SAUTE and stir in pepper chunks
Make the slurry by stirring together cornstarch and water. Stir into bubbling liquid, and allow to thicken
Hit CANCEL, and serve or hit KEEP WARM until ready to serve