Quote from elkpark
The accreditation process takes at least a couple years, and accreditation is retroactive to when the school formally started the process. If the school is an active candidate for accreditation while you are attending and ends up getting accredited, you will be a graduate of an accredited program, even if you graduated before the school was formally accredited.
Is the school's ADN program NLNAC accredited? If the ADN program is accredited and has been for some time, and if the new program is going to be in the process of pursuing accreditation while you're attending (actively in the process, not just saying they're going to apply), I would consider that a pretty minimal risk for you (chances are v. good the new program is going to get accredited). Otherwise, I'd look for another option.
Elkpark speaks the truth. I was in the exact same situation in my first RN-BSN program, and this was the exact same answer that CCNE gave me when I wrote to ask about accreditation. The program did have a long-standing fully-accredited diploma program, so I was confident that their BSN programs would also be accredited. If they already hadn't had a proven track record, I would have not applied.
I'm not saying definitely do it--after all, there is always a risk that they may not get accreditation and then you'd be stuck--but do consider these factors in your final decision.
For the record, it's my first RN-BSN program not because of any fault of the program: they were a brick-and-mortar program but I had to move out-of-state, so I couldn't complete it
They did get their accreditation with minimal problem so had I been able to stay and finish, all would have been well.