Nihilism....the rejection of all religious and moral principles, in the belief that life is meaningless.
synonyms negativity, cynicism, pessimism
Atheists are happy people enjoying life knowing we are free of all the religious constraints.

I could not support the idea of having no moral principles or thinking that the world has no meaning at all. Cynicism and skepticism have their place of course, but not as my personal life goals. I would not put atheism and nihilism in the same category...they are not 'one in the same' to me at all.

I prefer no "isms", which imply a philosophical classification. I am an "atheist", I do not study its philosophy, as there is none.
Religion has philosophy. Science used to be called "natural philodophy" until it was realised that, unlike alchemy, it wasn't based on musings.

Nihilism has nothing to do with atheism!

I had not heard of Nihilism until i read your post, so I looked it up.I might sound crazy here, or maybe I don't truly understand Nihilism, but it sounds like someone who is deeply depressed or suicidal.

This may help, I personally try to avoid label's. Which is better I guess its a person's choice.They are not the same.
Morality or lack thereof seems to me to be part of the process. What is right or what is wrong, Is this a concept that exsists? What is the meaning of life?