Which course is good for better job prospects: BBM or BBM with LLB?

For expertise llb is require. for managerial post bba and bbm are best option.

Sampurna if you want to a job as managerial capability than BBA/BBM is good choice for you

It depends on what field you want to work. If you want to be a legal manager or the role where legal knowledge involves, then you must have LLB if you want to hold managerial position in business function, ideally you should have MBA from a tier 1 or tier 2 institutes. Decide on this and accordingly