You could always decorate the old tire I use tires as planters, but I paint them Or you could take the tire concept and build something with walls about as high as a tire with a center open for them to sit in.
I have had peafowl for years, and I have found it doesn't really matter what you buy or build for them, they will always nest somewhere else..lol
Mine will build there nest where they feel the safest. It may not be the spot I would have picked, but they ddidn'task me... I tried the tire thing, boxes up high, they never cared for them. The seem to prefer on the roof of the coop or in tall grass.
Mine never did mess with each other. The males on the other hand did not like roosters, and would kill them.
The chickens and peahens nested together with no problems. But is was rare. The peahens preferred the ground in tall grass or the roof of the coop.
They liked places they felt they were hard to see.