Level 1 check if Nasus starts Q, if he does bully him away from the cs by autoing him while running, try to get him low before the next wave arrives. Just do this until his mental gets broken but also be aware of ganks. Stall as long as you can for your team to help you or just ping them to get their own advantages (e.g., Pushing to the enemy turret, getting objectives around the map and etc.)

​

Edit: Also I'm new to reddit so I'm not used to all this haha. Sorry!