Alternatives include using a hash table and using an ini file.
For the hash table you would use something like
.hadd -m Nicks $address $addtok($hget(Nicks,$address),$nick,32)
.hadd -m Nicks $address $addtok($hget(Nicks,$address),$newnick,32)
Now this will only store the information into the hash table, which is stored in RAM, thus, if you want to preserve the information between sessions, you will also need to save the information using the /hsave command, as well as load the information when the script starts using /hload
Recommended reading /help hash tables.
If you want the information to be displayed, you'll need to use $hget and/or $hfind, depending on just what information you actually want displayed.
The big advantage to using a hash table rather than a text or ini file, is that it is extremely fast, thus if you have a lot of people join the channel in a short period of time (such as after a netsplit), a hash table will be able to keep up with the modifications necessary, but a text or ini file might not, due to the speed limitation of having to access the hard drive.