Are you saying there is no sane reason to believe humans have an immortal soul that survives bodily death?
Death is the separation of the body and soul.
The body obviously needs the soul to survive (otherwise, it wouldn't be a body, but a corpse).
But the soul, which is spiritual, does not need air or nourishment or any other bodily assistance for it to survive. Strictly speaking, it doesn't need the body to exist.
It is spirit, not a physical thing. Without the soul's animation, the body dies and decomposes into many parts, no longer unified, no longer held together.
But the soul has no parts. It has no geographical location. It is simple. It is one. Yet it is manifestly real.
"Mother Nature," on the other hand, is manifestly a metaphor, a personification, a literary device.
That's fine as far as it goes, as long as we don't use it as a replacement for God -- which is not a metaphor, not a personification, but ultimate reality.
This is the sincere conclusion of countless sane and even brilliant men in history, both ancient and modern.
Only a knucklehead would seriously try to defend the reality of the tooth fairy or Father Time or Mother Nature. Not so when it comes to God's existence.