BSCS - the most general/mother field. You can do this and go towards hardware/software anywhere. If you go into this field your focus should be on problem solving.
BSSE - This is more related to software development and the process of software development. How do you manage big projects, risks etc.
BSIT - dunno about this but NED names its BSCS course to BCIT. so they teaching the same things as BSCS but under BSIT, depends on which uni is offering.
While both of BSCS and BSSE are different, you won't feel that much of a difference here especially in govt Unis as the courses are somewhat the same. If you are interested towards hardware side more you can consider Computer Engineering (CE) as well. That being said, BSCS is still the general field, so i always prefer that especially if you plan for further study like masters etc. You can always do BSCS and then join a software house and just code and stuff
Just check the course outline of CS and SE from any Uni you consider joining. You'll get an idea how it will go. BSCS courses tend to have more science related subjects like maths/electronics etc.