To answer the OP's question, Kaplan's Master's degree programs for nursing has received accreditation by CCNE. The Board of Registered Nursing in California has a list of approved NP programs in their website. This list only includes in-state NP programs so Kaplan being an online school from out of state is not listed. Graduates of out of state NP programs are eligible for certification as NP's in California if the applicant is nationally certified as a nurse practitioner (i.e., certified by ANCC, AACN, AANP, PNCB, NCC). In addition, California reviews the transcripts and makes sure the curriculum matches California's requirements. National certification boards (i.e., ANCC, AACN, AANP, PNCB, NCC) require that the applicant graduated from a CCNE or NLNAC accredited NP program.
I am not a graduate of Kaplan so I can't comment on the quality of their program.