[It would have been helpful to continue in or link to Temperature sensor address search not working, how to debug? New to arduino but not programming - #3 by jimjamjahaa. ]
You’re using the Nanode to receive the data from the emonTx V2?
Why are you sleeping it at the end of loop? That means you’re ignoring anything that comes in while you’re asleep - apart from what might be in the RFM69’s buffer, then just waking up for a quick peek, then going to sleep again. Your main loop in the Nanode should never sleep.
[And I’m not even sure that JeeLib uses the RFM69’s internal buffer in the mode we use!]