Here's why:
* "Scot" is already a common and accepted shortened form.
* Nicknames are usually informal and playful, and a 3-letter option might feel too abrupt or lacking in personality.
If you're looking for a fun nickname for a Scotsman, you could consider:
* "Mac" (short for "MacDonald" or other common Scottish surnames)
* "Jamie" (a popular Scottish name)
* "Cal" (short for "Callum", another common Scottish name)
Ultimately, the best nickname will depend on the individual and your relationship with them.