I personally think, that firstly we should rather ponder on whether Nehru was a dictator or not. Let us start from the definition of a dictatorship:
dic•ta•tor•ship (dɪkˈteɪ tərˌʃɪp, ˈdɪk teɪ-) n.
1. a country, government, or the form of government in which absolute power is exercised by a dictator.
2. absolute, imperious, or overbearing power or control.
3. the office or position held by a dictator.
As we can see, a dictator holds absolute power in a country, mostly by a reign of terror. It seems quite logical given that free citizens tend to fight off when a signle individual tries to impose his or her thinking over everbody else's. On the other hand however, why would Nehru want to become a dictator when the vast majority willingly handed the reins of a country to him every election? Why waste their support in order to get something he practically has already had?
These questions bring us to the main topic - what would have happened if Nehru had become a dictator? Suprisingly, I would say that his power would decrease significantly for he would lose a lots of followers, also from his party. Some people argue that he wouldn't even be able to go through with the plan because of lack of military power at Nehru's command which would be essential for ensuring his place as a dictator.
All in all, it seems quite possible that Nehru, having all the power he needed up until his death gave him the luxury of not needing to organize a coup d'etat. Question is - wouldn't he do that if he had lost any of his elections?
That is an another topic though.
That's one of the sides of that discussion, you can use it as a template for writing your own essay :) Remember that this kind of task should nourish your ability to express your own ideas and beliefs, so instead of using mine, try producing yours based on what you can read above.