Eelzor,
I don't find it hard to look after but I have spent a lot of money on additional equipment to make things easier. For example, an automatic top off device as the change in salinity in a nano tank due to evaporation is way higher than in a larger tank. As there is only a small volume of water compared to 55 or 75 gallon tanks any problems will become an issue much much faster. You need to be aware of the type of problems and have the necessary information available so that you can deal with them quickly.
As with anything read, research, read, research, etc. ad infinitum. The more information you get the better.
A bigger tank is easier to look after but I did not have the room for a larger tank and was prepared to spend the extra money on stuff for the nano.
Cheers, Eddie