Kind of. Both halves are present; it's that they can't see each other.
All of the braced statements can be nested, but you have to put both sides in the same container. For instance, this would work perfectly fine:
<<if>>
<<nobr>>
<</nobr>>
<</if>>
But this would break (and already did, as you just saw):
<<nobr>>
<<if>>
<</nobr>>
<</if>>
Even if the if statement is true, it checks for errors and for when it needs to stop considering the <<nobr>> before actually evaluating it. I'm not sure exactly what form this problem takes in the settings screen, but I need to recount the <<if>>s and <</if>>s used to say "minutes" and "hours" only when you have a plural amount of them.
This game would've been beyond impossible if I didn't have a sudden inexplicable drive to make this the best damn BE game you ever did play halfway through. Everything you expect to be simple, that you don't even think about when you see it, probably took over a whole page of code. Nothing "just works", everything takes a stupid amount of background work to assemble all the pieces that wouldn't be nearly as much trouble if it didn't have to adapt to an ever-changing value.
Except the commas in the numbers, apparently that's just <<=$size.toLocaleString()>> with javascript and it just fucken works. Bit of a shame, too; I'm pretty sure I could do that with my own code by using rounding and logarithms.