There seems to be two prevailing methods for removing nose badges and emblems:
Method #1: Dental Floss
Slide some dental floss or tape under the badge. I use dental tape because I think it's stronger (but I haven't actually used the string). Work the dental floss back & forth, “sawing" at the adhesive under the badge. It may take a couple pieces of floss if the adhesive is stubborn. This may take a while but this method is less likely to scratch anything.
Method #2: Small Screwdriver
Lay down a thin towel (like a shop rag) at the edge of the badge and wedge a small flatblade screwdriver underneath the emblem. This is a very common method but it makes me nervous so I usually use the slower Dental Floss method above.
After removing the badge or emblem, I use Goo-gone to get rid of the adhesive residue followed by some alcohol pads to prep the surface for the new emblem.
These are the methods that I and others have had success with but of course, we can not guarantee that everyone will be able to accomplish this without scratches—if in doubt, we recommend a competent & expereinced body shop to do the work.
Good luck!