i dont know about the content that they ACTUALLY have, but by right, these two are different by definition.

BSc in software engineering is a general science degree in software engineering, where at the lower part of the study, u will still go through more or less general science related to IT/computer science

BIT in software engineering should be a more focused learning in the specific field.

but that is by term lah. not sure what they ACTUALLY have there. do check on the total amount of credits each qualification require at graduation. might be some difference.