Heat remaining oil in cooker over medium heat. Cook onion, stirring, for 5 minutes or until tender. Stir in garlic and cook for 30 seconds or until fragrant. Stir in rice until opaque. Return chicken to cooker with stock and wine. Stir to combine. Secure lid. Bring cooker to high pressure over high heat (keep an eye on cooker as 5 minute cooking time will start as soon as cooker reached high pressure). Reduce heat to low to stabilise pressure. Cook for 5 minutes. Quickly release pressure using the release pressure method. Remove lid. Stir in parmesan and butter and stand for 5 minutes, covered, for rice to absorb remaining liquid. Stir through spinach and season. Serve with extra cheese.