She is looking for a place to nest so give her one. I have four amazons, a male/female YNA pair and a BFA/YCA both females that love each other - the YNA female is sitting on an egg (they accidentaly broke the first one) inside a large cardboard box that, apparently, was good enough (they destroyed ten or more boxes before they 'decided' this one was the 'one'
) and the two females have been chewing boxes, cardboard and even the paper on the bottom of their cage like there is no tomorrow.
Now, I know that there is a school of thought that says not to give them nests or nesting material during breeding season but, if you ask me, this a misguided notion that causes them nothing but anxiety because it certainly does not stop them from producing sexual hormones or curtails in any way their drive for reproduction so why not give them what they need? Chewing/building a nest gives them release from the anxiety and satisfies their drive so the whole thing ends up being easier on them and on us, the keepers.