What serial chipset does it use?What operating system is your computer running?Popular chipsets are the CH340, CP2102 and FT232 (most likely fake)
Should be printed on the chip. You can also go into the device manager on your computer and go to either the serial port or it might show up as an unrecognized device.If you bring up the properties there will be an option to update the driver.From memory I think the FT232 is supported by practically everything, the CH340 required drivers on earlier machines but worked fine straight away in Win10. The CP2102 was initially unrecognized on my Win10 but after choosing to update the driver it worked fine.
Not sure what is wrong in that case. The only thing I can suggest is trying different ports, USB cables and a different arduino if you have one to find out what the cause is.Where did you get the nano from? If it was from china via ebay etc... then it is probably one of the fake chips. They normally work but won't have the same quality control.
First download arduino ide then go to ...device manager >then click on ports >then there will be a option showing ur device(but the board name is nt mentioned) > install driver softwares by browsing frm the IDE Folder and ur device will show now in app... Hopes it will workCHEERS !