I've heard of chicks getting out of high up nests in trees, and I've had them 'bounce' out of nests that were higher than I wished they were and they were fine, (once up about 4.5 feet, I'd been trying to keep something soft below, but of course that day there was nothing much!) but that's PRETTY DARN HIGH!
Chicks are so light, and their fluff is so well... fluffy, it actually slows their descent and gives them some bounce, but... yeah, that's probably too much to expect. Thing is, even if you try to move her, she'll probably just abandon it possibly climbing higher. Maybe you could try moving it to a somewhat high, hidden spot in a barn/shed, but be prepared for her to abandon it and try for another tree nest. Otherwise, just leave her and let the situation play out, hard as it may be.... I think I'd put together some kind of small pen and put her AND her nest in it with some food and water. She won't like it, but...