I think the rarity of held items on wild Pokemon may have been altered a bit this game. I'm not talking about Dex Nav exclusive items, I just mean in general.
For example, I was Dex Nav chaining Venemoths looking for Silverpowder, because you can only find it on wild Pokemon this time around. According to the ItemDex they have a 50% chance of holding it. However, 50 moths later I had 15 Shed Shells and no Silverpowder.
I then went to Dex Nav chain Masquerain and got a Silverpowder within 10 of them despite the ItemDex saying that they only have a 5% chance.
So, my point isn't that the chance of held items has increased, since the Dex Nav does tend to increase the chance of held items anyway. My point is that some Pokemon, such as Venemoth, may no longer hold the same items as in X/Y.
Or maybe I was just incredibly unlucky.
I think Quincy has it right, considering that Pelliper don't usually hold Lucky Eggs in the wild...My understanding is that dex nav alters completely which items pokemon hold