Currently, Voltage’s managed BTCPay server doesn’t provide built-in Nostr Zap notification integration. You’d likely need a middle layer, a small service or bot that:

1. Listens to Lightning payments on your LND node or via BTCPay webhooks.
2. When a payment (Zap) arrives, constructs and publishes a corresponding Nostr event (like a Zap receipt) to notify your Nostr client.