A nano is the unofficial smallest of the geocache sizes. The official choices are Micro, Small, Regular, Large and Other. Nanos can be evil little hides or quite easy to find depending on the surroundings. Most nanos are small cylinders that have a magnet on it for easy placement. Of course there are a lot of diffenrent things that can be used as a "nano". You may need to bring a TOTT (Tool of the Trade) in order to pull the log out of the container. Sometimes getting the log back in is the hardest part of finding a nano. . .or at least in my case.
This hide is just one small example of what can be used as a nano container. This one should not be particulary hard as there are not a lot of options for where it could be. Sunday morning could be a really busy time at GZ and would be best avoided. Make sure you pull into the parking lot and not block the road. You will find out very quickly that this is a busy traffic area. It always suprises me for some reason.