Nigeria is unsafe in general, but you can get by. Some places in Abudja, Kano or Lagos seem to be viable, but never believe that!
Never forget, 95% of the population has nothing, while they believe you do. In many people's eyes their own life has no value, not talking about your.
No need to move around with guards, but a trustfull driver is a must. Don't expect low cost accomodation when looking for safety. Rely on referrences in any case.
Good luck, and bail out as possible!