When building Italeri's Nimitz-class carrier, there are several things to consider, as others have posted.
If you build it as Nimitz, you'll be doing OK if you intend to build it as the ship appeared in the late 70s. If you intend to build it as the Nimitz looks today, much of the kit's island and radar tower will require either aftermarket PE or a lot of scratch building to get it right.
As each of the Nimitz-class ships go through their mid-life refueling and complex overhaul, they get a new mainmast, new tower and different antenna rigging. Sponsons along the hull are changed and the defensive weapons suite is changed.
The modeler is very lucky with the excellent photo gallery available on the Navy's website navy.mil. Good, high res photos are available for free download that can make modeling a current ship much easier.
The kit is a good one and with some research, and some aftermarket tweaking can become an excellent model.
Enjoy yours.