Nusa Dua is the "resort area" of Bali where most of the major hotels in the international chains and the like are located.
It is a very well arranged and organized area, with gardens to lawns, controlled traffic, good beaches protected from the swell, etc.
It is not the most characteristic area of the island nor where you will have more contact with local life, but it is a good destination for those who like this concept of holidays and resort accommodation.