[werk_ag]

Jim, I can bet that there isn't any problem with any of your nanos, as both units are working. To me the issue seems related to the radio module.
How frequently the LED blinks on both units? I suspect that the led on the problematic unit blinks only occasionally or with a lower frequency than the one that is working properly.

Could you try testing it with another antenna, or even without antenna? Does it change anything?