Are two nights in the 40’s F safe for the plant?
We have a forecast for the next two nights to have temps in the 40's. Should I bring in my plants or are they safe for this brief dip in temp?
This would depend on the type of plants you may be referring to.
Your perennials should be fine.
Potted outdoor annuals and tender perennials should also be fine in the 40's, but sometimes it's more stressful to wonder about them than it is to cover them or move them temporarily inside.
If you have placed your indoor plants outside for the spring and summer, I would move them indoors until temperatures warm back up.
If you cover plants for the overnight cool temps. make sure your remove the covering in the morning.