Nick uses chronological order to relate his narrative. what effect does this have

The correct answer is this. When Nick relates his narrative in chronological order he captures the attention of the reader in order to involve him in the sequence of actions. The reader can show interest in those actions and probably tension can be generated too. The sequence of the chronology can make people think of what is going to happen next.  

In the excerpt, we can read how Nick remembers his childhood moments on the farm. And he does not feel sure how is going to be living in the city, close to his grandparents home. This can create some kind of uncertainty on the reader’s side to know what the future will be for Nick.