Choice Band and Swords Dance is a big no-no because Chocie Band locks you into a single move until Decidueye switches out. If you were to do a Choice Band Decidueye, here's how you do it:
-Leaf Blade
-Spirit Shackle
-U-turn
-Brave Bird
Nature: Adamant/Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Choice Band
Decidueye also hates Knock Off, as it's weak to it. I also wouldn't recommend using Swords Dance and Nasty Plot together on BP Decidueye, as it makes it massive Taunt bait.