No, completion of an MSN degree does not always qualify one as a Clinical Nurse Specialist. For a definition of the Clinical Nurse Specialist role, refer to this FAQ from the National Association of Clinical Nurse Specialists' website: http://www.nacns.org/faqs.shtml
The nurse practice act in some states allow for an overlapping of roles between Clinical Nurse Specialists and Nurse Practitioners. In these states, education at the graduate level (master's or doctorate) and national or state certification (or both) are required to receive the legal designation as a Clinical Nurse Specialist. CNS' in these states can prescribe medications and are eligible to apply for a National Provider Identification Number for billing of their clinical services to insurance companies similar to an NP.
In other states, the designation and role of Clinical Nurse Specialists are not clearly defined. In these states, there are no title protection for the CNS role. However, you'll still find nurses who hold the CNS title in these states and many do perform roles traditionally held by CNS such as staff development and education, nursing research, direct patient care, and expert consultant in nursing and health care related issues. However, qualifications are usually loosely defined and although many CNS in these states have graduate degrees, their educational preparation varies greatly.
It sounds like you are interested in a master's entry program in nursing. Many such programs exist across the US and a list of these programs are available here: http://www.aacn.nche.edu/Education/pdf/APLIST.PDF
(see page 4). However, you'll have to go to each individual program to find out whether their master's entry program have an advanced practice nursing component as some do. In those programs, the graduate level portion of the program may prepare you for advanced practice nursing roles such as CNS or NP. In others, the MSN is either a generic master's degree for nurses or a Clinical Nurse Leader program. Clinical Nurse Leaders are discussed here: http://www.aacn.nche.edu/CNL/Index.htm