I'm not a Sub-Zero player so I'm not going to pretend I know all his bnbs, but check out the Sub-Zero page Kombat Akademy and you'll see they have combos for various skill levels. They also have general information on the character that you may find useful for building your gameplan.
www.kombatakademy.com
You can piece combos together based on whatever you have equipped. The only special he has that really changes his combo paths will be Rising Ice, where he pops you into the air.