Sorry, I didn't think of that!
do a find on "trim(./)", then do a ctl-home.
start recording a macro, press the Find Next (defaults to ctl-l if I remember). Now you have the first trim highlighted. Do ctl-x to put it into the clipboard, type "nvl(", ctl-v, ", ' ')" and stop the macro recording.
Now press f12 repeatedly.
Marco, when is regex going to be upgraded to handle this?