Were you planning on putting it on the viv bottom? Is your viv for a cham? Is it solid sided or screen mesh?
Moss can be tricky and many varieties have pretty hard sharp spines. Moss isn't recommended for cham cages. If you free range your insects they just hide in it and die or start eating the fecal matter and who knows what else that gets stuck in it. It can mold if constantly wet and chams are sensitive to stagnant vivs. Also, if they shoot at insects on the moss they can also pick up sharp spines of moss on their tongues and swallow them. Bad news for intestines.
If you want the moss to help keep up the humidity there are safer ways to do it. Fogging, more misting multiple times a day, add lots of bushy live plants, and drape plastic sheeting on the sides of the cage (loosely).