Is there a way to sell the GTS without getting hurt?
Yes. Well, its going to hurt anyways, but it won't break your nose. The person is supposed to fall, and hit the knee on the way down. If you'll notice, Snitsky pretty much landed on his feet, which forced Punk to lift his knee with more force than normal. And thus, broken nose.
JBL is only 10 pounds lighter than Snitsky. He took the GTS and his nose didn't get busted.