What is the best nature for Dialga?

Answer 1

Or

+ Atk.sp. - Atk
Cuse he haves a lot of special Atak and a little atak

Or

+ Spd. - Atk.
Cuse like this he cold atak first and with he's huge atka sp. he can win


OR

If you thik that he haves to little speed to puch him up or so many atk.sp to have more, you can give him a nature that defense is incrementated, becasu he is week vs earth and fight....
+ Def - Atk

Answer 2

The best nature for Dialga is typically Modest, as it boosts its Special Attack stat while reducing its Attack stat. This allows Dialga to take advantage of its high Special Attack stat and hit harder with moves like Draco Meteor and Flash Cannon.