I had the opportunity to host Nuxt 3 SSR on Vercel, so this is a note for reference.
For the build settings, I needed to set the Output Directory to .output/server as follows.

For enabling CORS, the following article was helpful.
https://vercel.com/guides/how-to-enable-cors
Specifically, I was able to handle this by placing the following file at the root of the project.
There may be incorrect descriptions, but I hope this is helpful.