Picking a Nikon d5100 camera lens?

Would a nikkor 35mm f/1.8g be good for taking self portraits but also taking other pictures like nature? By the way this is my first. I have no idea about any of this

No, it's too short for portraits, and way too short for nature photography.

The 18-55mm is great for landscapes at the short end and can do decent portraits at the long end - although many prefer the 50mm f1.8 for the latter.

For nature/wildlife you'll often want a long lens, look at the 55-200mm/55-300mm. Closeups need a micro (Nikon's name for Macro) lens or extension tubes.

A 35mm or a 28mm lens is the lens most likely used for scenic's. Because they inherently have a great depth of field (focus). That means if your main subject is like 50 feet away and your distant subject is 1/2 mile away the entire picture will appear sharp and clear, as long as you use small f/stops like f/11, f/16, and f/22. With portraits you want a longer lens. The minimum in the digital world is a 50mm. I'm older (age 70) and most my portrait subjects are older also. As a result I like a 135mm or 200mm lens, the reason for this is that these focal lengths "compress" the face so that big ears and noses are not over emphasized. And the f/stop situation is reversed with portraits. You want to use more "wide open" f/stops, like f/5.6, f/4, f/2.8 etc. If you are young say age 30 and younger you can get a way with the lens on the camera now if it is like a 28-to-50or55mm lens. Just use the long end of the zoom or 55mm.