Who is she, Tengu...?
It could be a big job. I had to go to a customer about jackdaws in his chimney once, He had a proper bird guard on the pot and had even wired it up to, but the jackdaws had managed to pull off the wires and get in, the nest was 4 foot down the chimney, how the birds got in and out was/is beyond me. I had to push the nest all the way down the chimney in the end, to get rid of it, and that took some doing, there was so much of it, I had to use lengths of batton to push it down, and when I pushed it down as far as I could I had to go and get another length to join to the first bit. The amount of stuff that came out the bottom was amazing....
You will need to wait till the youngsters have fledged btw, shouldnt be that long....