Gods realm, how do you get out? Achieve Nibbana in this realm?
From the perspective of the old Pali scriptures, I am not aware of anywhere that states: "It is more difficult to achieve nibbana in the a godly realm than in the human realm". 

For example, AN 4.123 describes Nirvana ("unbound") in the god realms. 

I think the answer to this common view is based in the type of 'godly' realm. 

A most common godly realm in the Pali scriptures are higher meditation states (jhana), as described in AN 4.123. 

However, there are godly realms that equate to luxurious wealthy lifestyles of sensual pleasures (e.g. MN 37). It is possibly this godly realm called The Sensuous World (kama-loka) that makes it difficult to achieve Nibbana.


  Good sir Moggallana, the Vejayanta Palace has a hundred towers, and each tower has seven hundred upper chambers, and each tower has seven
  nymphs and each nymph has seven maids. Would you like to see the
  loveliness of the Vejayanta Palace, good sir Moggallana?