You don't have a trademark on the name NastyPenny.
Of course, I don't have a trademark on the name "NastyPenny." I never claimed to have one on the name "NastyPenny." However, I do have a trademark on "Bitcoin Penny." Inserting the word "Nasty" into the middle of "Bitcoin Penny" is the infringement.
I am no expert on IP law, however I dont think this would be an infringement. The infringement, if one exists would be from the use of in code we trust on the backside of the coin (he didnt use your actual coin, did he? If so then I dont think there is any grounds to argue infringement) where it said in code we trust and similar.
As I mentioned previously, additional research needs to be done on IP law to give an opinion one way or another.
Cases of trademark infringement are rarely open and shut and as such these types of disputes can result in litigation, the outcome of which is often unclear until a ruling has been made.