If you go into bed, activating night mode would only work if you stay in the bed because once you get out of bed it will be deactivated 
so
I will assume that when you get out of bed the lights turn ON being night lights and when you get into bed the lights turn off.
You could use this blueprint but you would need to create 2 automations or you could use this blueprint (sensor Light) and download my other blueprint “
Turn Light, Switch or Scene On & Off with Trigger Conditions” and use this for your bed sensor. It has a selection for entity as the trigger.
This is how I would set it up.
Use this blueprint (sensor light) make all your selections, don’t use night lights and select the "Use The Time Options " for say “on time” 7am & the “off time” 10pm. Now you could just use this blueprint again or my other blueprint but we need to create another automation for night time. Create another automation, dont use night lights but set up the normal lights for your night lights. Make your selection using your bed sensor as the trigger and set the "Use The Time Options " for “on time” 10pm & the “off time” 7am.
Now is should work.
Hope this helps you and I have got it correct.