I'm a Canon user. Although I believe it's the same principle with Nikon, in using lenses. 70-300mm lens will really work. I have a lens similar, it's also 70-300mm, only it's Canon. It's good for shooting, especially for subjects like fishes, plants or other things around the environment. This lens is all-around, even for portraits, for events, for studio shoots, outdoor shoots, etc
For me, this kind of lens is a wise buy.

Remember, it's not all about the camera or the lens. 50% of the beauty of your photos are basically from the photographer itself.