Will an expunged misdemeanor of nolle prosquoi show up on an FBI background check?

If there was a "nolle prosequi" as to you where the misdemeanor was dismissed by the prosecution, there will be nothing to expunge because there was no criminal conviction. However, on a background check of the person with the dismissal, it will show that the person had been charged with a particular crime which was dismissed.

The only way to possibly prevent the reporting is if the court issues an order sealing the criminal file of this particular person. Whether this is possible should be based upon a consultation with an experienced criminal defense attorney.