Only the Shield of the Oversoul will be destroyed. If the creature is green, it will not be destroyed.
10/1/2009 If an effect would simultaneously destroy Shield of the Oversoul and a green creature it's enchanting, only the Shield is destroyed.
September 2, 2015 11:16 a.m. Edited.
Remember to check the Gatherer rulings before posting a question. Gatherer rulings include FAQs and other relevant clarifications that answer most questions typically asked about specific cards.