I ve got some problem with the nano included in the raduino you could have the same with all blinking ? clones or genuine : it seems that one output was shorted to ground making great current consumption (about 200 mA) and atmega and 7805 heating ... this could also happent with nano tested with blink as soin as the shorted atmega pin is not the led one.
the best could be to use a true ? test program (and hardware) testing each pin as input with test contact, and in output with led.
less time consuming : using nano on support, if any problem or doubt, check with another one (having one validated nano could permit to put some bad one to garbage, avoiding hours trying to debug another part)
