Is nihilism the logical extreme of atheism?

[Mudhammam]

Even this possibility is insufficient - if the result of human existence is brought about by god's will then the purpose, meaning or value of human life would be subject to god's will. That makes it subjective. Going by this definition, nihilism should be the logical extreme of theism, not atheism.

Perhaps. However, if God's will is the ideal, the most perfect good possible, the locus of meaning, the essence of value, the purpose of purpose, per se, then...?; whether or not these are actually meaningful concepts or merely abstract phrases unduly placed in the form of a question--devoid of intelligibility--is, again to repeat myself,

another matter.

I think it basically boils down to whether or not any ideal is properly considered objective or not. If not, then it's only personal preference, and nothing is quintessentially better or worse off for it. If we can agree that certain ideals are binding in some way, through logical necessity or what have you, then the theist could just substitute God for the ideal, and avoid your nihilism, could they not?
Here, admittedly, I seem to have contradicted myself earlier by stating that

Outside of intentional design... as in God, I can conceive of no other possibility for what might be considered objective meaning, purpose, or value.

And then:

Why must objective morality or value depend on the imposition of an outside being rather than one's self that exists, relatively briefly, in an objective material world?

Rather, if ideals are objective, then it would seem that objective values can exist in a godless Universe (I think the confusion on my part arose from conflating meaning and values), although with regards to meaning and purpose, I still think existential nihilism logically follows from atheism.

Buddhism provides an adequate counter-argument to that. Buddhists don't believe in a gos, but they believe in the law of Karma - a universal moral law inherent and intrinsic to human nature and one that provides your life with objective purpose, meaning and value. That is the problem with "atheism implies nihilism" argument - it assumes god can be the only possible source of objective meaning etc. whereas we know there are many alternate sources.

I'm not sure I quite understand the rationale in how a "a universal moral law inherent and intrinsic to human nature and one that provides your life with objective purpose, meaning" can follow where the existence of such laws are only defined by individuals in a particular species (values, as in morality I think, requiring separate consideration, where the universal moral law seems tantamount to the ideal).