Place butter in a multicooker; heat on sauté mode until melted. Add bacon and cook, turning occasionally, until crisp, 4 to 5 minutes. Transfer to a paper towel to drain, leaving the butter and bacon drippings in the pot. Add onion to the multicooker and cook, stirring, until starting to soften, 2 to 3 minutes. Add potatoes and broth. Turn off the heat. Close and lock the lid. Cook at high pressure for 10 minutes.