You need to figure out what program you are looking at. LPN and RN programs are completely different and separate. But it sounds like you are going for your RN, and a two-year degree is called an Associates Degree in Nursing. These programs have prerequisites in biology, chemistry, anatomy & physiology, etc. The nursing core itself takes you two years to complete, because you must take the courses in a specific sequence. Upon graduation with the ADN, you are eligible for becoming a Registered Nurse (same licensure as if you graduated from a 4-year baccalaureate program).

An LPN program is usually not very competative for entry, there are usually no prerequisites. It is a year long course, and you do not earn an associates degree. You are only eligible for LPN licensure.