At my school, PNMs got nametags issued by Panhel for round 1. At the other rounds, each sorority would make up nametags based on their themes. So PNMs didn't have to worry about making their own nametags.
You will want something memorable, maybe indicating a hobby or interest of yours, but easy to make. For example, if I had to make a nametag for rush today, I would probably make a little cross-stitch design of my name, because one of my hobbies is cross-stitch. I might even draw in a little needle and a stray thread.
You might make a nametag that looks like film, with sprocket holes and the like, if you're into photography. Just an example.