AutoHotKey is good if you don't like typing. Hotstrings can be created for text replacement purposes. The syntax for Hotstrings is like this...
::ntm::nice to meet you
So if you typed... ntm ...into the chatbox, then hit enter... nice to meet you ...would be posted into the chat.
The abbreviation can be whatever you like, as can the replacement text, and you can have as many Hotstrings in your script as you can think of, or remember!
Once you've installed AHK (AutoHotKey) you can use Windows notepad to write your scripts in.
To write your first script you can use my example above. Just open Notepad, type in...
::ntm::nice to meet you ...then save your notepad file. The important bit is when you save the file. Normally, a notepad file will have
.txt at the end when you save it, but for the AHK script to work, it has to have
.ahk at the end instead. You can name the file whatever you like but it must end with
.ahk For example,
myFirstScript.ahk
You can now close notepad. Go to where you saved the file, the file icon won't look like a notepad file icon, it looks like a sheet of paper with an 'H' on it. Double click the file to run it. If the script is running you should see an AHK icon 
in your system tray (next to your taskbar clock).
To test out the hotstring, open any program into which you can type out text, type in the hotstring abbreviation, in this case it's... ntm ...then type a space or hit enter and you should get... nice to meet you ...appearing on the page.
This can be a bit inconvenient sometimes because anywhere you type the abbreviation, you get the 'nice to meet you', but you can specify where you want the hotstring to work so that it doesn't become a pain.
You can stop the script from running by right clicking the system tray icon, and selecting 'exit' from the menu.
Have fun. ; )