Set Instant Pot to saute mode. Once hot, add oil followed by butter.
Season Chicken breast with salt and pepper. Sear 2 minutes each side in hot Instant Pot. Keep aside.
Keep the Instant pot in saute mode and throw in potatoes. Fry for 4-5 minutes, stirring in between. Potatoes will begin to look light golden brown.
Stir in minced garlic. Cook for 30 seconds. Then add chopped onion. Cook 2-3 minutes until it has softened and starting to caramelize.
Pour in chicken stock. Place chicken breast at the top. Throw in rosemary.
Switch Instant Pot to the Manual Mode and set the timer to 5 minutes. Let it go do high-pressure mode and then the countdown will begin.
Once the timer is over, the switch of the Instant Pot. Let the pressure release for 8 minutes. Then release pressure manually using back of a spatula.
Remove chicken breast, keep aside covered.
Set back to Saute Mode. Add half and half, honey and balsamic vinegar. Season with salt and pepper. Add chilli flakes if desired. Stir well.
Add Chicken breast back to the Pot and coat with cream sauce.