ABILITY: Magic Bounce (See below for Healer)
Nature: Quiet For Trickroom. If not using trickroom both Calm and Modest will work
252 SpAtk/252 SpDef/4 HP
Hatterene is a weird Pokemon is has all these moves and an ability that screams "I'm the party healer!" But this things special attack stat is so high it also screams "I'm your special attack sweeper!" I'm going to showcase my "party healer" set. NOTE: This is mainly a doubles set. Don't use this thing in singles as it can't attack well. And it's healing moves become more niche.
Life Dew/ Heal Pulse - life Dew restores both Pokemon but Heal Pulse restores more but only one Pokemon at a time. (Could use both if you want :p)
Aromatherapy - This is preference. If you have the Healer Ability you have a CHANCE at restoring an ally's condition. Aromatherapy guarantees all Pokemon in the party to have their conditions healed. Honestly, Magic Bounce is too good an ability to pass up. So if you have Healer Don't use Armotherapy, And if you Have Magic Bounce consider using a move slot for this
Trick Room - A standard of most doubles sets. A lot of slow Pokemon get to hit hard and fast. And in Hatterne's case, It gets to heal First.
Psychic/Dazzling Gleam - Preference, both are good powered STAB, Psychic does do more damage but again, preference for your overall team composition.
Finally, Depending on if you don't use both life dew/heal pulse or Psychic/dazzling gleam (which you could do) a very niche move you can experiment with is Healing Wish. Healing Wish causes the user to faint but if you switch into a Pokemon that has low health or a status condition it will be healed. For me, this is too situational, but it's a very good last move to do before you die, as the effect will last over several turns until the conditions for it to activate happen.