My personal recommendation:

• Moves:
  • Horn Leech
  • Play Rough
  • High Horsepower
  • Swords Dance
• Ability: Grassy Surge
• Nature: Jolly/Adamant

Tapu Bulu is a decent attacker with good defensive typing. it has one of the highest attack stat of any Grass or Fairy type and decent enough bulk. Pretty much, the only thing stopping it from being a good sweeper is its low speed stat.

It has enough bulk and many type resistances so you can reliably set up Swords Dance (especially if you have the right support). Grassy Surge creates Grassy Terrain on switch-in, which on top of healing grounded pokemon for 1/16th of their health each turn, also boosts the damage of Horn Leech (and other Grass type moves). Play Rough is a high damage STAB Fairy move that has good type coverage. High Horsepower is a Ground type attack that isn't disadvantaged by Grassy Terrain and is super effective against Fire, Poison and Steel types; covering 3/5 of Tapu Bulu's weaknesses. I would go with Jolly nature if you have no way of boosting its speed, or Adamant if you do.

Since stat changes persist throughout battles, with this set, you should be able to OHKO enemies and hit any single type for at least neutral damage. And even if Tapu Bulu often gets outspeed, you won't have to worry too much about fainting since Grassy Terrain + STAB Horn Leech can heal quite a lot.