Fin/ish
Nest is only one syllable.
No, you do not divide a one-syllable word. The word is pronounced with a single stress point.
fin
The word plant has one syllable. This means that there is no syllable divide for this word.
finish
Grim-ace, divided as "grim" (1 syllable) and "ace" (1 syllable).
tooth
jour-ney
sam-ple
re-treat
Rob-in
of-ten