Well if you think about it bitwise, like if these 2 "values" were being loaded into a register...
NULL is just 0
NaN is nonzero
thus NaN is bigger!
NaN is neither nonzero, nor isn't it nonzero. Dividing anything by NaN yields NaN again, which is neither nonzero, nor isn't it nonzero, nor is it infinity. Whereas when you divide a non-zero number by NULL, the result will be infinity. Therefore, the real question is whether NaN not being infinity not or not not being infinity is worth more than x/NULL, with x!=0, which always gives infinity.
Wait. ... ...
Theeeeeerefore, NaN is bigger. NULL means invalid, but the result of a computation that uses NULL as one of the operands is not necessarily invalid, whereas NaN always stays NaN, never mind you push or pull or accumulate or pop it.
Hear ye: NaN is he true dominator of thy scientific number cruncher, whereas the fool NULL hides deep deep in thy pipeline.
a developer, programmer, and coder. And for bonus points, a software engineer!
... and of course there's "hacker", to make the confusion even worse.
Personally, I mostly use the nouns "[software] developer", "[software] programmer", and the verbs "hacking", "tweaking", "coding", "programming" (so basically all of them). I don't put too much meaning in those.