Maybe the question is misleading (I am a German native speaker myself), let me give you an example. I want to nominalize the verb stellen in the following sentence:
Wir haben etwas online gestellt. (We put something online.)
But, since the word online describes where or how something was put (gestellt), how would the nominalization look like? I could think of
Nach dem online Stellen
Nach dem Onlinestellen
Nach dem Online-Stellen
whereas the second option looks false to me.