It is easy making AI for board games (*cough if you are at least good at the game cough*. Just make it so if it is a specific situation it does something. (Ranomizing is usually needed to make it interesting)
Example:
A simple AI for tic tac toe would be like:
If you can win, take it.
If middle is open, take it.
If corner is open, take it.
Random open spot is open, take it.
(Yes, I know Tic Tac Toe is not Chess; its just a little example.)
Your going to have to make a part that makes sure you cant put yourself in check, and same with the computer

If you can put them in Check, do it.
If you can kill a piece, do it (and if you want to get difficult make it check to see importance of what kills it and if it can be killed)
Randomly move a piece?
Chess has too much for it, and Starcraft AI making would be a little difficult and lots of triggers. (I could never make a Chess AI because I are t3h suxx0rs at Chess)
My phone has Chess and they have it so the phone (Computer, whatever) has a specific script to use, unless something interrupts it. (I learned it so I make the game unable to do anything

)
Good luck
