Well al info was help for the last set of questions but here's my problem now.
The little iggy is beating the crap out of the bigger one. She/he? is chasing the other one in to the other side of the tank and trying to bit it,Afterwardsthe little iggy nods it's head yp and down. Just trying to make sure that this means my little mystery is claiming it's space? and for the record we are finding another tank for the other iggy.

Iguanas are territorial. To be put simply, the larger iggy does NOT want to share his space. The other thing it could possibly be is courtship, but if either of the igs are under 10 inches in length from snout to vent, then thats probably not it.

Either way, the best decision is to get another set up for one of the iggies to keep them seperate, which you are doing.

Thank You