I was getting the same error string on a Nano clone from a kit. Thank you to everyone who suggested to run the program with the ATmega328P (Old BootLoader) selected as processor. That fixed my problem. I also found helpful the advice to test my Nano unit with the basic blink sketch. I got the same error running blink, changed the bootLoader and blink worked fine. Then I ran the program I started with and that uploaded fine as well.