Importing Content Without Including `nid` I have this site I develop, and the way the process works is that I have three versions of the same site: Production, Staging, and Development. 

I've been working on some new features on Development, but over time, new content has been added to the Production version. Now that I'm done with the development for now, I'd like to copy the new Content Types + Nodes I've created in Development to Staging, which I've turned into a clone of Production, but I keep running into this issue: when I import content, it always includes the nid, so it overwrites content that has been created on the live site, which I can't have.

I've tried Features, Data Export Import, etc, but they all include the Node ID with the information, so existing content is always getting overwritten when I import.

What solutions are there for importing nodes WITHOUT also importing the Node ID with it? I essentially need to use Node Clone's functionality, except instead of creating the cloned node locally, it exports it to be created on the Staging site.
I think you should use Features and Universally Unique IDentifier.

When you update an existing node, thanks to UUID, it will be updated in production site because they should have the same UUID (but can have different IDs). If the UUID doesn't exist, then it will create a new node.