Nance got paid like he a surefire starter, but has a long way to go while Rozier already proved he can be effective.
What troubles me with Nance's game, even though I like him in general, is that he is not a 5 (can't defend the rim or control defensive glass) nor a 4 (can't shoot). And when you are a big with no clear position and you aren't as skilled, you are destined for mediocrity. I'd rather use Theis who is cheaper, better shooter, rebounder and rim protector with some ability to move his feet.
This trade would weaken us and if we are just looking to move Terry, which we are not, I am sure that better deals would be available.