- Slice the potatoes into rounds about ¼ an inch thick. I used a mandolin. 
- Add the potatoes to the Instant Pot with the chicken broth. 
- Cook for 2 minutes on Manual > High Pressure Cooking 
- While the potatoes cook, prep the remaining ingredients and preheat the oven to broil. 
- Spray a baking dish with cooking spray. 
- When the Instant Pot indicates it has finished, quick release the steam. 
- Open the Instant Pot. Remove the potatoes and place them in the baking dish. 
- Hit cancel on the Instant Pot and then Saute. 
- Add the garlic to the pot and cook for 1 to 2 minutes. 
- Add the milk, cream, salt, pepper, and onion powder, 1 cup of cheddar (save ½ cup), the parmesan reggiano, and cream cheese to the pot. 
- Stir continuously until the cheese and cream cheese have melted. 
- Drizzle the potatoes with the liquid mixture. Sprinkle the remaining cheddar throughout. 
- Broil for 3-4 minutes until the cheese has melted. 
- Remove the pan from the oven. Sprinkle the chives throughout.