I'm not sure which specific novel you're referring to. Different novels have different important chapters depending on the plot, characters, and themes. For example, in a mystery novel, the chapter where the big clue is revealed could be a very important 'capitulos da novel'.
To analyze the 'capitulos da novel' effectively, you need to pay attention to the language used. The author's choice of words can give hints about the mood and significance of each chapter. Also, look at the relationships between characters in the different chapters. Are there new alliances or conflicts? Another aspect is the foreshadowing. Check if there are any hints in the earlier 'capitulos da novel' that lead to events in later ones.
Nisekoi After Story would most likely build on the original plot of Nisekoi. The main characters who were in a fake relationship in the original might face new challenges that test their real feelings for each other. There could be more exploration of their backstories, their families' influence on their relationships, and how they grow as individuals while dealing with their complex love situation. It might also show how their friendships with other characters evolve as a result of the relationship drama.