Postprocessor output is written in plain text format.
As soon as you would start formatting your NC output (in any kind of format), i am afraid your NC controller will not accept the output anymore.
Also if you would do this, the NC listing in NX would not show you the font and color as you would expect it, since that is just plain text display.
If you would like different fonts and colors for display only, you might consider to look for a specific NC editor, or another text editor that can highlight certain parts of text, based on certain characteristics. Notepad++ can be configured to do a kind of syntax highlighting that would be useful to accomplish what you are looking for.
Ya........I was concerned about the formatting characters causing an issue. I think I have to basically have two files one that is formatted and one for the machine, unless I create a program that formats then prints and then strips out the formatting back to plain text.
I open the program with WORD and do a repace. I replace "*" with "*" and bold. then hit replace all. then print and close without saving. My post out puts a row of ******** before and after the tool change line. so having them bold makes it stand out.