I know this is a day old and most people who would have seen this already have moved on, but this is a simple fix. In fact if you have secure boot enabled, the Nvidia driver installation will detect it and start the signing process. If you don’t have secure boot enabled, then it will skip it. I think having secure boot enabled and properly signing your drivers is good to not end up in that situation again. Though I understand how annoying it can be too. Sigh