Good morning,
I'm confused. You state that, "I received my certificate this summer...". Have you already taken the nurse investigator course???
A Nurse Investigator is an RN or an LNC who has training/experience in medical record investigation which is the primary focus of the investigator career. There is only one entity that offers education/certification as investigator:
http://www.lniinstitute.com/ - CLNI
It is not quite the same as LNC. CLNI is also offered by the same entity that educates RNs as LNCs.