Place a 6-qt Instant Pot on Sauté, Normal/Medium setting then add butter.
When melted, add onion and garlic and cook until softened. Stir in salt, pepper, and thyme.
Add potatoes and chicken broth. Scrape up any browned bits from the bottom of the pot with a spoon.
Pressure Cook on High for 10 Minutes . When the time is up, allow for 15 Minutes natural release, then carefully quick-release the rest of the pressure.
Mash potatoes slightly for a chunky texture.
Stir in broccoli, 1 cup of cheese, and sour cream, cover and let mixture stand 5 Minutes.
Ladle into bowls and top with remaining cheese, bacon, and green onions and hot pepper sauce (if using).