On the Google Play Store when you review a app right now it says posting publicly as my full name. Also on Google Maps when you review a place you been the same thing it says posting publicly as my full name. How do I change that to my Google Nick name or something different then my real name!
From Write a review on Google Play (emphasis mine)
You can leave a public review for apps, games, and other content on the Play Store. When you review something on Google Play, the review is linked to your Google Account and is public. You can view and edit your Google Account at aboutme.google.com. If you don't want a review to be public, you can delete the review.
Something similar is mentioned in Write reviews and add ratings of places
If you don't want that the name of your "main" account be shown, use a secondary account.