I am looking for any documentation on how to integrate strapi with an existing NextJs/React application.
Welcome to the Strapi Community Forums @Phillip_G
I think that it won’t hold any information in the docs regarding how to “integrate it”
If you have an existing NextJS application, you can build a new Strapi Project, and use the same data, mimic the same data structure and collections etc.
Then you consume it like any other API etc. You might have to change the way it’s consumed etc but the data could then be the same.