Place the ham on a large piece of foil. Make slices halfway through the ham.
Combine the brown sugar, mustard, balsamic vinegar & honey in a small bowl. Whisk to combine. Spread the brown sugar mixture over the ham to coat.
Close the foil around the ham to cover it completely.
Place the wrapped ham on a trivet in the pot insert.
Add water for presurizing to the pot.
Secure the lid, close the valve, and cook on manual high pressure for 18 minutes.
Allow for a natural release for 10 minutes, then quick release the remaining pressure.
Carefully remove the ham. Let rest in the foil for 5 minutes.
Remove the ham from the foil and transfer it to the serving platter.
Pour out the water from the bottom of the pot. Take the liquid that has been trapped in the foil with the ham and transfer it into the pot.
Add the pineapple juice, remaining water & cornstarch to the pot.
Cook on sautee, whisking frequently until mixture has thickened to your desired consistency.
Drizzle the sauce over the top of the ham prior to serving.