MacBooks are notorious for aggressively sleeping and pausing background network tasks (known as App Nap) to save battery. Follow these steps to ensure Waiver Sniper fires successfully.
Never rely on battery power for overnight waiver runs. macOS battery management will eventually suspend Chrome's background alarms regardless of your settings. Keep your Mac plugged into wall power.
The absolute most reliable way to guarantee execution on a Mac requires zero downloads. You can use a built-in terminal command to block idle sleep while allowing your screen to turn off safely to prevent burn-in.
If you prefer not to use the Terminal, you can download a free third-party app called Amphetamine from the Mac App Store. Click the pill icon in your menu bar before bed to start a "Keep Awake" session.
Ensure Google Chrome is the active application before you walk away. Do not close the window. You can minimize it, or simply let the screen go black using the Caffeinate trick above.