how do i insert chord members, or symbols?
If you are asking how to just insert a member of a chord, press Ctrl-enter instead of enter. This can be done with any notehead.
Symbols would probably be inserted through text, with one of Lawrie Pardy's ...Dings fonts.
Someone (probably Lawrie) has actually made a chord font, I believe, if that's what you're asking about. You can find it in the Scriptorium. To use it, first download and install it. In page setup, set one of the User fonts to the chord font (and remember which number). Open your character map and copy the chord you want. In NWC, insert text, using the appropriate number User font, "at next note/bar" centered above the appropriate beat using the character copied from the clipboard.
Now I'll go make sure there's actually such a font...
Okay...http://nwc-scriptorium.org/ftp/helpful/fretqwik400k.zip
But it looks like in this font, you need several characters in that text string to create a chord. However, this makes it more usable, since it's not limited to a certain set of chords!