Can I edit the metadata of each chunk?

definitely, just node.metadata["key"] = "val"

Updating a node thats already in your index is a little more annoying though

But like if I want to add the page url, video url if in the page contents etc that's possible with node.metadata["key"] = "val"?

yea it is -- that code is just updating the metadata of a node

Can I do that in at the llamaclound level?