How can I customize the page of view item form nintex 2013 (the page of edit and new item are different than view item)
could you post some examples what you mean with difference?
with nintex forms, you design only one layout of 3 new/edit/view forms.
the difference just might be that in view (some) controls are rendered as 'read only' and possibly if formatting rules are applied some controls/blocks might be hidden conditionality.
Retrieving data ...