So just leave the inside alone and hope it doesn't grow mold and make sure the ants have plenty of water so they can hydrate it themselves.
It won't mold if you keep it dry, only thing that could maybe mold is dead insects they carry in but since it is dry in there the insect will dry before mold can form. But as I said you have to know if your species can live in a dry nest. So don't force them out of their test tube nest, connect the wooden nest in addition, add a heating source and see if they move by themselves. Ant species who live in soil require almost always a moist nest, but in my experience a lot species that live mainly in wood don't necessary need a moist nest, but as I said try it out. I only know some European species who don't need a moist nest, but I have no idea about NA species.