Your deployment experience depends on your branch of service as well as a variety of factors, including your nursing experience and personal desires.It's difficult to predict any one person's deployment experience as an ICU nurse. That will depend on your assigned deployment team.
Many ICU nurses are assigned to larger field hospitals with several hundred staff, while others are assigned to remote surgical teams of as few as 5 or 6 people. Others perform transport missions in fixed wing or rotary wing aircraft. Some serve on one of the two Navy hospital ships.
Deployments can be as short as 3 months while others are 6 or 9 months. Some locations have many amenities (running water, AC, and even Wifi) while others are glorified tent cities.
I'm an Air Force ICU nurse currently deployed in a large inpatient facility with many amenities. I know another Air Force nurse going to a bunch of tents in the middle of nowhere with a small surgical team.
It's just not possible for me to give you a good idea of what to expect without knowing your personal interests, branch of service, skill level, and level of physical fitness.