Place the corned beef brisket into your Instant Pot with the fatty side up.
Add in 2 cups of beef stock, the garlic, the spice packet that came with the corned beef as well as 2 tablespoons of pickling spice seasoning or your own custom mix.
Seal the Instant Pot and set for 1 hour 25 minutes of high pressure cooking.
Allow for natural release. Should be 20 minutes or under.