Is there an in-game way yet for me to see a list of which production nodes I've invested in, without having to physically click on each node on the map to see the production nodes? I invested in a lot of excavation/mining/farming nodes but there was never an easy way for me to see which ones. (I'm playing again for the first time in 6 months and trying to catch up on all the changes.)

Sadly, no.

If you hover your mouse over your CP in the top-left of your screen, it'll show you how much CP you've used in general categories, so you can see how much CP you've invested in nodes, but it doesn't actually give details, so it's borderline useless. And for the rented items, it doesn't even display the right number (for me at least, it routinely displays 19 instead of the correct 20).

You can toggle Production Node Information on the world map to make it look like this:

Makes it a little bit easier to manually check through the node network at least.

Thank you for that tip, it's certainly better than nothing! And yeah I have no idea what 10-CP item whichever one of my characters has rented. 🤷‍♂️

The most likely candidates are a storage container or a fence.