Is it correct to use two nor's?

You should use "nor" twice.

Thanks, hightor.

Did you mean to say, "You should not use "nor" twice."? If so, how should it be rephrased?

It's more common to use neither/nor, which is the negative version of either/0r.

Let’s look at our lives as a very rare existence, and one which we shoulder our ancestors upon. If we do so, we won’t look upon it simply like a child looking at his toy, neither will we oversimplify it nor be too carefree or casual.

izzythepush's rephrase is a better way of expressing the thought. But if you are talking about two or more items, once you use "nor" you don't use "or". Your example is technically correct but not as clear as the revision made by izzythepush.

Thanks to both of you.