Heat olive oil in inner steel pot of pressure cooker set to Sauté on Normal. Cook and stir rice, onion, and garlic in oil until onion is translucent, about 4 minutes.
Pour vegetable stock into the cooker and stir to break any large clumps of rice into grains; add fresh mushrooms, shiitake mushrooms, nutritional yeast, miso paste, white wine, salt, and black pepper.
Lock pressure cooker lid in place and set steam vent to Sealing. Select Pressure Cook (Manual) and cook for 10 minutes on High Pressure.
Set steam vent handle to Venting to quick-release pressure.
Stir risotto and let cool for 5 minutes; garnish with parsley to serve.
