Can you play Nocturne (found via Stacked Deck during a showdown) to a contested battlefield?

Ruling: You cannot play a unit to a battlefield you do not control. As an attacker, you never control the contested battlefield, so you cannot play Nocturne to it mid-showdown. As a defender, the battlefield is contested but still under your control, so you can play units to it during the showdown.

Sequence:

• Attacker goes to a contested battlefield
• Showdown occurs
• If attacker plays Stacked Deck and finds Nocturne, they cannot play it to the contested battlefield (no control)
• If defender plays Stacked Deck and finds Nocturne, they can play it to the contested battlefield (still have control despite it being contested)

Nuances:

• A battlefield can be both contested AND controlled by the defender simultaneously
• Control, not contested status, determines whether you can play units to a battlefield