I think if you were nominated through a stream that doesn't require a job offer than -no- Cic would not require a job offer either.
However, Cic holds ultimate discretion over who receives Permanent Residency and before they can grant PR they (Cic) must be satisfied that the applicant can:
A) economically establish and
B) will stay in the nominating province
So, obviously having a job offer within the nominating province is certainly better than not having a job offer. Having a job lined-up will go a long way in convincing an officer that you're capable of economically establishing and that you'll stay in the nominating province.
However, Cic holds ultimate discretion over who receives Permanent Residency and before they can grant PR they (Cic) must be satisfied that the applicant can:
A) economically establish and
B) will stay in the nominating province
So, obviously having a job offer within the nominating province is certainly better than not having a job offer. Having a job lined-up will go a long way in convincing an officer that you're capable of economically establishing and that you'll stay in the nominating province.