Yes, you can wear your Lief overnight. In order to mute autodosing overnight, navigate to Menu > Settings > Vibration, where you can choose to mute your device for up to 12 hours. That way, you won't be disturbed with autodosing while you sleep.
However, please keep in mind that Tap Doses can still be initiated even if you've muted autodosing. As a result, if you accidentally knock into your Lief in the middle of the night, a 3-minute Tap Dose will begin.
If you tend to move around while you sleep, consider wearing Lief's athletic strap on top of your Lief and stickers to help keep them in place overnight.
In general, we recommend that you ideally wear your Lief during waking hours so you can actively participate in monitoring your real time data throughout the day, and engage in the Downtime practice during moments of acute stress to help restore balance to your autonomic nervous system.