Balls don't really need a nesting box - when they are about ready to lay they will push the substrate out around where they are going to lay and then lay in that (if you use newspaper you'll probably miss this little prelay clue). Most likely she will lay over the heat or in her hide if it is big enough (if it's not you might want to remove the hide when she nears laying).
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Tosha 
"Nihil facimus sed id bene facimus"

11.42.0 Ball Python (Harry and Fluffy and gang)
1.0.0 Angolan Python (Anakin Skywalker)
0.0.1 Green Tree Python (Verdi - yeah I know but my kids love the book)
0.1.0 Bredls Python (Smurfette)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Desert Tortoise (Pope John Paul aka JP )
2.2.1 Fish (1,2,3,4)
0.0.0 frogs rescued from pool skimmer