This is my first guide so try and be gentle. I am a Nova with the master skin and through all those games I have tweaked different guides until I decided to make my own.

-First talent is hands down Ambush Snipe. 20% extra snipe damage from stealth (or 1 second after stealth is broken) is really nice. Also combined with the other talents you can burst pretty much any hero down or at least scare the **** out of them.

-2nd Talent is really up to you. I choose Gathering Power because it's a DPS increase.

-3rd talent Anti-Armor Shells because it adds to the burstyness of Nova and Nova is all about bursting.

-For the Ult I choose Triple Tap because it does more damage and the lvl 20 talent makes it really really nice.

-5th talent is Lethal Decoy because again its a DPS increase.

-6th talent is Crippling Shot. The 25% increased damage is awesome because combined with Ambush Snipe makes for a really nice burst.

-Last talent to pick is Fast Reload. Correct use of this can wipe an entire team. People say Nova is bad at team fights. With this talent you can pick people off with massive amounts of damage.

Now for the rotation.
-First toss out a Holo Decoy (With Lethal Decoy the decoy does 25% of your damage including your abilities)
-Follow with a Pinning Shot (With Crippling Shot you, your decoy, and your teammates do 25% more damage to the target)
-Finish with the Snipe and Auto Attack (If done correctly you will have the 25% increased damage from Crippling Shot and the 20% increased damage from Snipe which ends in bad news for the person you targeted)

All of this needs to be done within about 1 second and after that second you need to make the decision to Triple Tap, keep auto attacking, or getting the hell out of there. It's all situational.

Thanks for taking the time to read the guide and I hope to see you in the game. :)

Enjoy