Now you're really demonstrating ignorance. Ships can't be "hidden", like subs can. So, the nuclear power to a sub a far different matter, to that of a naval vessel, especially the size of an Aircraft Carrier. Now, the Navy is working on some version of "stealth ships", but how they are powered remains a non-issue
Here's a hint as to the issue.......can you guess how many tons of fuel a typical non-nuclear powered Aircraft carrier requires?? Can you guess how much space on an otherwise already cramped ship, it would take up??
If you can figure that out, compared to the same space requirements in powering a nuclear powered aircraft carrier, you'll start to grasp the importance of nuclear power to naval ships, especially carriers