To anyone having the same issue suddenly not having oxide on their server who also has Nitrado for gamehosting.
Here's a solution on how I solved mine.
1. Downloaded the latest version of Oxide for Rust from:
https://umod.org/games/rust2. Extracted the oxide.rust.zip to a Temp folder.
3. I stopped my server via Nitrado's Web Interface for my Rust server.
4. Unchecked the check box for "Activate Oxide," at the very bottom of the General settings page.
5. Started the server without Nitrado's pervious install of oxide.
6. Stopped the server via the web interface.
7. Connected to the server folders via my Filezilla FTP client.
8. Moved the folder named, "RustDedicated_Data" from my Temp folder to the root directory of rust (i.e. /rust) and overwrite all, upon the pop-up prompt.
9. Start the server via the web interface.
10. Enjoy running server with oxide rust working again.
Thank you Wulf for you quick reply. Your support is much faster than that of Nitrado's tech support, which sometimes I may need to wait days to get an an answer and not always a wise one.