So I tried...

I tried to take the derivative of:
Y=OPTIMUS
But the
multiplication and chain rules started making it giant. I finished it,
but then when I tried to multiply it all together, I realized: Finding
(OPTIMUS)' just isn't worth it.

Chain rules? Are all those letters a function of x (or whatever variable you're taking the derivative of)? Of course, if they're not, then the answer is zero.
If it was something like dy(x)/dx where y(x) = o(x)p(x)..., yeah, that could get hairy if those functions can't be composed. In that case, maybe start with a numerical solution and work backwards. But without definitions of those functions, I wouldn't rule out the possibility that there is a trivial solution lurking behind the corner using simple function composition.
I think you just gave up without trying so you could make a lame pun.

It ended up being way simpler than I thought it would be. No chain rule, just nested multiplication rules. Here's (OPTIMUS)':
Y'=O'PTIMUS+OP'TIMUS+OPT'IMUS+OPTI'MUS+OPTIM'US+OPTIMU'S+OPTIMUS'
Every letter is a variable and this is the simplified form.