I thought L&T had a clutch tool that holds the inner section of the clutch while tightening the starter nut - I may be thinking Horstman - It has been a while.
If you're in a pinch, you could use a piston stop. Not my favorite method. If you do use it, roll the piston way below TDC and thread the stop down as far as it will go in the cylinder head. then roll the piston back the stop and tighten the nut. If you don't have a piston stop, I know some that have used rope that is pushed inside the cylinder (through the spart plug hole) to fill the volume in the head. It works...