I'd like to know more about what's happening so we can sort this thing out.
What's the exact display of the Google Nest Hub?
Are you using its original power cable for your device?
Have you already tried performing the recovery mode to see if there are improvements? If not, please follow these steps:
Place the device in Recovery Mode (unplug the device then hold down (long press) the volume up and volume down buttons while the you plug the device back in. Release the volume button once the device turns back on.)
Attempt a factory reset once device boots into Recovery Mode (hold down (long press) both volume up and volume down buttons at the same time.)
Let us know how it goes by responding to this thread.