As Jeremy has pointed out just use what you feel most comfortable with for any given shooting situation. At the risk of merely stating the obvious I will offer a few observations though.
The 18-55 kit lens is intended as a general purpose lens that will cover most situations but as it has a limited wide aperture it is not going to be great in less than perfect lighting conditions. You can of course boost your ISO in dim lighting but push that too far and you run the risk of "noise" spoiling your shots. I use the 18-55 or my 18-70 for general street shooting and when I need a wide (ish) panorama such as in landscapes although dedicated landscape photographers usually want something even wider such as a 10-20 or similar as shooting with a cropped frame camera multiplies the focal length by a factor of 1.5 in Nikon's case or 1.6 for Canon non-full frame cameras. So your 18-55 is really operating as a 27-83 focal length lens.
The 55-300 is a long telephoto lens useful for pulling in distant subjects so shooting sports when the participants are a long way off is a primary use as is shooting wildlife either in nature or in zoos and safari parks. It will also serve as a portrait lens in the 80mm and above focal range.
Your 50mm is a good portrait lens but some models feel uncomfortable with the photographer so up close so the longer focal length of your 55-300 will allow you to shoot from a greater distance. A telephoto lens is also good for candid photography in the street or park or wherever you don't want your subjects to be aware you are shooting.
Be aware though that some people don't take kindly to "sneaky" pics and may object if you are seen photographing them. Always be prepared to delete pics if people object, although this doesn't happen a lot.
I hope this helps a bit with your lens choice decisions.