For Publishing the NopCommerce Application website below is the step:
Step : 1 - Publish the Nop.Web project.
Step : 2 - Publish the Nop.Admin project.
Go to the publish folder where your publish created
Here is your answer below (Step :3 is your answer) :
Step : 3 - Cut all dll from the Administration and Paste all dll to bin folder which in main bin folder for whole project.
Step : 4 - Copy two things from your source project and in App_Data folder Settings.txt and InstalledPlugins.txt which is not published in your publish file so paste this two files in your publish folder in App_Data. (You need to change the connection string in Setting.txt as per your database host).
Step : 5 - Now you need to copy whole plugins folder from your source folder (but remember this plugins folder you need to copy from the Presentation folder not from the main source where the solution file are there.)and replace it to with your publish's plugin folder.
Step : 6 - Now your publish have been ready.(now you can deploy on hosting server)