Prepare the Meatloaf Mixture: In a large bowl, mix all meatloaf ingredients thoroughly by hand until the mixture holds together.
Shape in the Bundt Pan: Spray a 6-cup Bundt pan (one that fits your Instant Pot) with nonstick cooking spray and firmly press the meat mixture into the pan. Cover the pan with aluminum foil, spraying the foil with nonstick spray. Puncture a hole in the center of the foil for steam to escape.
Set Up Instant Pot: Add potatoes, chicken broth, and garlic to the Instant Pot. Place the trivet on top of the potatoes, pressing it down slightly. Rest the Bundt pan on top of the trivet. Secure the lid, move the valve to sealing, and set the Instant Pot to Manual or Pressure Cook on High Pressure for 35 minutes. Perform a quick release once done.
Prepare the Glaze: While the meatloaf cooks, whisk together all glaze ingredients in a bowl and set aside.
Remove Meatloaf from the Instant Pot: Carefully take the Bundt pan out, draining any excess drippings. Use a spatula or towel to keep the meatloaf in place while draining.
Optional Caramelization: Preheat the oven to 400°F (200°C). Line a baking sheet with foil, coat with nonstick spray, and place it over the Bundt pan. Using oven mitts, flip the meatloaf onto the sheet. If it breaks slightly, press it back into shape. Brush generously with glaze and bake for 5-10 minutes, or until caramelized.
Mash the Potatoes: Use a potato masher to mash the potatoes, then stir in butter, cream, Boursin (or cream cheese), salt, pepper, garlic powder, Italian seasoning, and chives until smooth and creamy.
Assemble & Serve: Remove the meatloaf from the pan (or oven if caramelized) and transfer it to a serving dish. Brush with more glaze. Fill the center of the Bundt with mashed potatoes for a beautiful presentation, serving extra mashed potatoes on the side.