I agree that one way you can go about this is providing students with a graphic organizer including pictures. Before going on the nature walk, I would review or have a teachable moment where they learn converse about characteristics living and non-living things have. You could also find an age appropriate video explaining living and non-living things. This can be student led, but teacher facilitated. It is important for students to engage in inquiry in order to enhance learning. SInce the students are in Kindegarten, one way you can adapt this organizer is by having the students write 'L' for living and 'N' for non-living. This has student practicing their letters. If you are doing a 5E lesson format, I think this would be a great little engage activity to get students thinking about living and non-living things. From there, I would further your investigations by reading books to integrate literature within the lesson and by doing further research through games online or apps.
I hope this helps get ideas flowing. Good luck with your lesson!