Can you react to Accelerate being activated when an opponent plays a card (specifically, can Hidden Teemos trigger to search for Nocturne when opponent plays Ekko with Accelerate)?

Ruling: No, you cannot react to Accelerate. Accelerate is an added cost while playing/paying for the card and does not create a chain.

Nuances:

• Accelerate happens during the payment/playing of the card, not as a separate triggerable event