What nature should I get for her?

depends on what set you want to run

>>31333633
any -speed nature, and build it from there

>>31333633

depends on build

mixed sets that use stuff like Flamethrower and Heavy Slam go Sassy or Relaxed since Rocketfu's speed is slow anyway. Otherwise Impish/Careful for Phys Att. builds or Bold/Calm for Sp. Att. builds. EV train based on what you want to wall for and what you you want boosted on Beast Boost KOs.

File: tumblr_ohs6kb5jhZ1rtl8rmo1_500.png (85KB, 500x540px) Image search: [Google]

85KB, 500x540px

>>31333633
Are you using her as a wall? Then either Relaxed or Sassy.
As an attacker? Adamant or Modest with Choice Band/Specs or with Life Orb/Weakness Policy while running Automatize
She is versatile as fuck. The most flexible of all the Ultra Beasts.

I suggest you should run two of them. One for defensive sets and one for offensive sets.

I have had decent success with an adamant lefties subseeder with max attack and hp

>>31333633

Not OP, but is it possible to run a mixed set? I've been thinking about it, but really wasn't sure if I should opt for that or go for something solely Physically/Specially offensive.