This build allows for nova to pick off people while manage to escape easily. This is not a spec for you to chase someone trying to finish them off, if that is more your play style then I suggest getting "One in the Chamber" in replace of "Hot Shots".

There are a couple of ways to initiate a fight:

1 - (This is generally what I do) With "Ambush Snipe" you are required to use Snipe first, then auto hit, then Pinning Shot and to finish someone off use Envenom. Save Decoy for an escape.
2 - The only difference with this is instead of using Decoy as an escape, use at the very start, even before you Snipe. This will help with fighting a stronger Hero.

Once you get "Fast Reload" I suggest getting everyone as low as possible in team fights if you are unable to kill and then continuously Triple Tap until everyone is dead. This is a very effect way to win a team fight.