Using sauté mode, heat oil in a multicooker. Add mushrooms, onion powder, and salt. Cook, stirring until the mushrooms have released their liquid, about 6 minutes. Add sherry and cook until mostly evaporated, about 1 minute. Stir in green beans and broth. Turn off sauté mode. Close and lock the lid and cook on high pressure for 3 minutes. Carefully release the pressure manually.
Whisk cream, flour, and thyme together in a small bowl. Stir into the green bean mixture and return the multicooker to sauté mode. Cook, stirring until bubbling and thickened for 3 to 5 minutes. Transfer to a serving dish and top with French-fried onions.