Yes, there's no such thing as being a "general" NP -- all NPs have a specific specialization. There's also no such thing as a "general" MSN degree -- different schools offer different concentrations ("majors"), but you have to specialize in something
in an MSN program, whether that's a particular advanced practice specialty, nursing administration, nursing education, or something else -- but all MSN programs offer advanced education in a particular area or aspect of nursing
As you've found, not many schools offer an NNP program, because they have to have appropriate clinical facilities available to provide a good clinical education for the students.
Your choices would be to go directly into an NNP program (after completing the required nursing experience that is), or get another MSN first and then do an NNP post-Master's certificate. However, again, that would involve getting an MSN you don't
want and then completing nearly another whole Master's degree on top of that -- post-Master's certificates are a great option for people who already have an MSN and have now decided they want to change specialities, but I don't really see the point of putting in the extra time, effort, and $$$ into doing both programs when you could get what you want with one
BTW, I looked at the UCSF website just now (because it seemed v. odd to me that a school would have an NNP post-Master's certificate program without having a "regular" NNP program), and it looks to me like they do offer a "regular" NNP program:
"The Advanced Practice Neonatal Nursing (APNN) programs are two-year curricula leading to the Master of Science degree ... Students entering the neonatal specialty may choose either the Nurse Practitioner (NP) or Clinical Nurse Specialist (CNS) track."
Pediatric NP, Acute Care Ped NP, and Neonatal Adv Practice Nrsg Masters Specialty Areas - UCSF School of Nursing
(A "two-year curriculum leading to the Master of Science degree" is a regular MSN program -- UCSF may also
offer an NNP post-Master's certificate, but they do
have the regular MSN NNP program.)
My advice would be to relocate, if necessary, to attend the graduate program you really want (plenty of us have done that!) rather than make do with a degree that isn't going to get you what you want just because it's more convenient.
The other thing I would point out is that many people start out in nursing school, or in their nursing careers, sure
that they want to specialize in a particular area and, after they get a little experience and see more of the "wide world of nursing," they find that they're more interested in something else entirely. I encourage you to keep an open mind through nursing school and not get too fixated on wanting to be an NNP. Most people are completely unaware, until they've been in nursing for a while, of the incredibly
wide range of career paths and opportunities available within nursing -- many options that folks on the "outside" don't even know exist.