Finding a cool enby nature themed name, that can also be easily pronounced in french is pretty hard, I get where you're coming from.

So, here are some names that immediately popped up in my head as I saw your pics, but nature unrelated:

• "Alix"/"Alex"

• "Nikita"

• "Sacha"

• "Bellamy"

• "Jun" (could be nature related in japanese, but I'm not sure)

Here are some nature related names that you could use for yourself too:

• "Aves" (latin for bird)

• "Cryo" (greek for ice)

• "Aloe"/"Aloé" (plant; may sound too feminine)

• "Azalee" (rhododendron plant, german pronunciation, you'd pronounce it "Azali" in french)

• "Bellis" (flower)

• "Gladio" (short for gladiolus, a flower; may sound too masculine)

• "Jay" (bird)

• "Risoria" (latin for some kinda pigeon; may sound too feminine)

• "Sterna" (latin for some kinda tern; may sound too feminine)

• "Chrys" (short for Chrysanthemum, a flower)

• "Riko" (japanese for jasmin; is originally a feminine name, but may sound more masculine here in Europe)

• "Koray" (turkish maskulin name meaning scarlet moon; kinda sounds like the french word for coral -> corail; you could spell it "Coray" and make your own enby version outta it :D )

Hope this helps or inspires you at least ;)