I’ve never agreed with the idea that atheism leads to nihilism. All atheists that I have encountered tend to look on it more as the universe has no other keeper then we sentient beings, and therefore we must look after our children and the world that we are providing them, very carefully.
There are no take-backs, resets, or father figures with magical powers who will fix any screw-ups that we commit. If we mess up, our children, and great great great great great great great great grandchildren, will suffer from our arrogance and short-sightedness.
In a way, atheism inspires its believers to work harder and act with greater wisdom than the deist or other believers, who think that they are operating with a giant safety net.