Is there any way to change natures (Pokemon X/Y)?

Question

Besides breeding. I've got a couple Pokemon with bad natures, but I'm kinda lazy, so I don't want to keep breeding till I get the perfect nature AND ability.

Answer 1

Unfortunately, there is no way whatsoever to change a Pokemons nature, as it is part of the Pokemons Personality Values.

Answer 2

Unfortunately, no. But breeding with a Ditto with the desired Nature and holding an Everstone ensures that the baby Pokemon will have that nature.

For example, you have a Bashful Charizard, and you want an Adamant one.

Breed it with an Adamant Ditto holding an Everstone.

The resulting baby Charmander will always be Adamant Nature.

With that, now you only need to get the Ability right by RnG.

Hope this helps :)