I haven't been to Nazca nor Ica in years, but being Nazca a small town while Ica a city, I guess that once you see the Nazca Lines there won't be many other interesting things to do in the first location. Besides, while in Ica you will be close to Paracas (Ballestas Islands, sealions, The Candelabra), Chincha and Pisco (yeah the REAL Pisco town which was founded in 1640 not a renamed city in the 1930s, you Chilean girl
Here is an Ica map so you can have an idea on travelling distances.http://www.latindestinations.com/sharew ... %20Map.gif
You could also stay at "Las Dunas" hotel which is between Ica and Nazca. Pleasant place to stay with several pools, sport courts, horse riding and sandboarding.