Arguments against existence of God.

[Angrboda]

No one claimed that the universe was not created ex nihilo, so no one needs to prove it. I would claim that I am unaware of any scientific evidence that indicates that it was 'created' or 'came from nothing'. That would be sufficient reason not to believe the universe was created ex nihilo. No logical proof required, though some people claim that something can't come from nothing; they seem to be in the same camp that claims God did exactly that.

The absence of anything to prevent the universe’s coming into being does not imply the metaphysical possibility of the universe’s coming into being from nothing. To illustrate, if there were nothing, then there would be nothing to prevent God’s coming into being without a cause, but that does not entail that such a thing is metaphysically possible. It is metaphysically impossible for God to come into being without a cause, even if there were nothing to prevent it because nothing existed.

Reasonable Faith, William Lane Craig, Creation ex nihilo: Theology and Science