Have you ever experienced the joyful moment of listening to a song, watching a tv show or movie, or even just heard someone famous mention the area you live in or come from? I know I have! It seems so amazing that someone so famous could know about the humble place you are from. It is such a magical moment, and usually after that, you find a special place in your heart for that artist, song, show or celebrity. After that you always mention that your neighborhood, town or state is famous because "so and so" talked about it. You point it out when listening to that song, or watching that program. It seems like the best thing that ever happened to that area! This same thing happened to the prophet Nephi.
In 2 Nephi 25:5, immediately after we've read through almost 16 chapters of quoting Isaiah, we learn why Nephi chose to include that. He says "My soul delighteth in the words of Isaiah, for I cam out from Jerusalem, and mine eyes hath beheld the things of the Jews, and I know that the Jews do understand the things of the prophets, and there is non other people that understand the things which were spoken unto the Jews like unto them, save it be that they are taught after the manner of the things of the Jews."
So Nephi is experiencing exactly what all of us experience when we hear our homes mentioned by someone famous! He loves Isaiah, because he is talking about his home! I think not only is Nephi excited because Jerusalem is mentioned, but also because it has been a long time since he was home. Though Nephi knows that he needed to leave, because Jerusalem is going to be destroyed, it is still the place where he grew up and has such fond memories of, so it is natural that he misses it. Remembering the areas he had been to that Isaiah mentions is probably a wonderful, if not sad, trip down memory lane.