You can actually 1v1 anyone.

Phantom Dancer is actually so good on Nocturne because you already get flat AD from your Q to make use of the 30% crit. You gain up to 12% movement speed when near enemy champions which stacks well with your flat movement E, and maintain ignoring unit collision without relying on Q. The 12% less damage taken lets you duel anyone.

If you are ever in a 1v2 or 1v3 situation, try to land Q on the ranged enemies and kill them first. When a melee enemy is on you while you kill the ranged ones use your E on them to force them to back off and let you 1v1 or they get feared and you 1v1 regardless.

Late game I like to save Paranoia as an executing ability rather than to engage unless I am split pushing and need to join a team fight.

Use whatever trinket you like, the red trinket is important early game for ganks but I prefer the blue one to combo with R after I have items.