I wouldn't say nihilism is a philosophy, more the emergent result of holding the values that I do. My evolutionary path has been voluntarily cut off, so I have the freedom not to care about humanity's fate, I don't hold religious beliefs and was not trained in them, so I don't have a "spiritual" or moral perspective to uphold, I don't believe authority is positive for humanity, so I don't care about law or country.
From a pragmatic viewpoint, none of my views about what we should be doing is possible: Reducing the population and shrinking it's footprint to allow other life to thrive and evolve, abandoning the notion of nations, and especially armies and war, doing away with the idea of ownership of land, which leads to the dispossessed being little better than slaves, automating as much as possible and promoting subsistence in favor of productivity... I could go on further, but it would get redundant.