Drain the pineapple chunks, reserving the juice, and place the pineapple chunks in the bottom of the Instant Pot inner bowl. 

Place ham into the Instant Pot bowl cut side down, on top of the pineapple chunks, and pour the reserved pineapple juice over the ham. 

Sprinkle the brown sugar onto the ham, pressing it onto the sides of the ham so that it sticks. 

Place the lid on the Instant Pot with the valve set to sealing, and use 'Pressure Cook' or 'Manual' to cook the ham for 8 minutes. 

At the end of the cook time, use the 'quick release' method to open the Instant Pot and carefully remove the ham, and scoop out the pineapple chunks with a slotted spoon. 

To make a glaze from the liquid remaining in the Instant Pot bowl, set the electric pressure cooker to 'saute', and simmer the juices stirring often, until the liquid reduces by half. 

Drizzle the glaze over the ham. You can caramelize the glaze under the broiler for a few minutes if desired.