OneDrive or any other cloud service has a network channel between the folders you have selected to sync and your cloud space. In that sense, if you are saving your Nvivo project into a sync folder, it is similar to save your projects on a network drive. Nvivo Manual says that :
"By default, if your project is stored on a network drive, when you save the project your changes are saved locally—the .nvp project file on the network is only updated when you close the project. To avoid loss of data, make sure that you close your project before you turn off your computer."
It seems the unexpected restart of your computer preventer Nvivo to properly save your project, and as far as I know without a recovery file you can not recover your work.
I do use cloud storage to store my projects ignorer to access them wherever I need. However, I do keep my active project on documents folder and move and replace the copy in cloud folder after I finished my work. I highly recommend a similar saving routine to prevent such unexpected data loss.
Hope this helps,