As Shiningblue says above, the Marshall Plan was for Europe....Particularly, it was meant only for WESTERN EUROPE in 1948. That is why it is argued that (by some) that the Marshall Plan helped build the iron curtain across Europe. (Those who said 'yes please' and accepted the aid became more or less American allies during the Cold War.)
Regarding Japan, they also received economic aid, but NOT the Marshall Plan. The aid for Japan consisted of the Economic Reconstruction in Occupied Areas,(EROA-prog) and Government and Reflied in Occupied Areas (GARIOA-aid). These two programmes did not better the economy significantly, and Japan still suffered from inflation and the dollar-gap created after WWII. Therefore, Mr. Dodge was dispatched to Japan in the beginning of 1949 to make the Japanese economy blossom with his strict "Dodge Plan." However, it was not until the Korean War broke out in 1950 that the result of the Japanese economic reconstruction could be seen.
NATO was established in 1949, the Marshall Plan was announced in 1947 and took effect in 1948, hence, the Marshall Plan is NOT connected to NATO.
About education and government in Japan after WWII, again, this was not due to Marshall Plan. The reform you are probably thinking about were implemented by MacArthur, the SCAP-commander who was in charge of the occupation.
Hope this information was helpful!!!