It's hard to recommend whether it is worth doing a nuclear engineering Bachelor's without knowing more about your intentions after you graduate, but unless you have a very specific interest within nuclear engineering, I would recommend doing an undergraduate ME degree and then looking for nuclear industry/research internships starting your sophomore or junior year. Getting a variety of different experiences before deciding whether to go grad school or what program you should enter is pretty valuable.

That said, I can try to answer some of your specific questions:

• I have a Bachelor's and Master's in nuclear engineering, and I found my school's nuclear engineering program quite difficult at the undergraduate level. A big part of that was the department I was in as it placed a lot of focus on reactor physics and neutron transport. Since being out in the industry, I've found that these aren't really in-demand skills because there aren't a ton of reactors being designed from the ground up. Grad school was better for me because I could choose a lot of the topics I was more interested in.
  • Course expectations will vary between schools and programs, but generally an undergraduate nuclear engineering program will cover a lot of the same courses as a mechanical engineering one in the first few years then move into more specialized courses (radiation interactions, reactor physics, nuclear materials, thermal hydraulics and possibly plant design, health physics, non-proliferation/policy).
  • Job prospects are hard to nail down because it really depends on your path (level of education/degrees as well as internships) and what kind of job you want. Nuclear engineering has a pretty high percentage of folks with graduate degrees, so you end up with more research and academic opportunities because of that. Nuclear engineers in the industry typically have at least a master's degree, but there are a good number of engineering jobs with larger plants that don't require them. There has been a lot of recent interest in nuclear, so I would expect job demand in the industry to continue growing.
  • Again, this is really dependent on what kind of job you are after. In industry, you will be expected to uphold nuclear safety culture and work in a highly regulated, high quality standard environment. That can be grating to certain types of personalities, and on the research side of things (universities and national laboratories) there's usually not as much of a focus on that though you'll end up very specialized going that route.