To dream of calling someone using a nickname represents feelings of familiarity or having a closer connection to something than other people. Feeling good being an insider.
Positively, a nickname may reflect feelings of being more popular. Feelings about some area of your life being well known or having a sense of family.
Negatively, a nickname may reflect feeling good thinking of others in a demeaning way. Enjoying remembering people for their embarrassments. Alternatively, it may reflect a dislike of others being close to you or liking being close to you. It may also reflect a dislike of how others remember you.