On the humorous side.
You have a pet chromosome? How nice for you! However did you choose one from the 23 pairs you have? Well, you could call it micro-mini-me or mike for short.
If you like 'Nan' as a nickname, then yes, it is a good nickname.
Chromosome 7.
A good nickname for what? Sounds a bit pansy
autosomes
It does not require a nickname.
A good nickname for Sheila could be Shei or Shelly.
A good nickname for Zekrom would be "Black Dragon".
Jaz might be a good nickname
Well my friend is called Kristen her nickname is krissi.
There are 46 chromosomes in human cells.
Kenster, Ken, Kenny...
The good nickname for christian is chriss killr