1. Try to start at red buff, then crooks, then raptors and when you've done that your going to head over to the blue buff.
2. after you've gathered over 100 stacks, you might want to try your first gank to mid or top.
3. try to get your stacks to 400 at 20 minutes. that the ideal stack count.
4. Don't surrender because if you have 400 stacks atleast by 30 minutes you should win if you play right.
5. don't be early game agressive. Nasus does not do alot of damage early game. so you should't engage early game.
6. those are all my tip. good luck!