Every states nursing board is different. I do not believe you were rejected based on the severity of the charge but the recency of it and the fact that your situation with the court has not concluded.
For the FBON, they state that they look at severity, how long ago it was AND evidence of change (ie: rehabilitation). I believe that you would be able to become a nurse, you will simply have to check with your state BON to see what it will entail.