The nano will be easy to set up. Some of the maintenace issues with the smaller tanks are:
1. Temp. control...smaller volumes of water are more prone to temp. swings.
2. Evaporation...a little evaporation can have a larger effect on tank salinity and must be controlled.
3. Water chemistry/quality...with the smaller volume of water the quality can degrade quicker.
I have a 20 gallon and in all honesty, once you get temp and top offs under control there is little maintenance required...I do a 3 gallon water change weekly and dose calcium and alkalinity daily.