Alone Female is Broody? Need advice

Hello!
I have a 4 yr old single female named Opal, who I'm fairly sure is broody? Lately, she's been being very... "flirty" with her toys, and I've noticed her frequently hanging out in the corner of the bottom of her cage for the past couple of days. She would come back up and want out though, so I always assumed she was just ripping up the paper towels down there for fun. Well, just today, when I went near her cage, she got very angry and puffed up, doing that funny rocking thing they do when they think they've found a potential nest. When I got a little closer, she actually charged at me, hissing. I have chickens, so I'm familiar with broody hens, but I've never dealt with it in cockatiels before, so I was wondering if anyone had any advice? She's usually very tame and cuddley, so you can imagine my surprise when she started acting like this, lol

I'm assuming that I should just let her be and try not to stress her out.. but like I said, I've never dealt with broody cockatiels ;u;
One thing I am a little concerned about though, is that the corner she's picked has some poop there. Could that be a problem? I'm worried that if I try to change the paper towels, she'll get really stressed out, but I also dont want her sitting in poop... help?

Thank you!!