So the purpose of this build is two fold. Disable and hamper the enemy team, while simultaneously keeping your team alive. I find this build works best in full on team fights, the bigger the better.

Level 1 Grenade Calibration
This can really turn the tide in a team fight. Suddenly they're all weaker and your team is all healed, and once it's fully powered it's incredibly useful.

Level 4 Overdose
Early on Overdose helps keep you healed, and once you hit your level 20 talent, makes the enemy team go night night super fast.

Level 7 Debilitating Dart
This talent works two fold. It helps during an escape, but can also help prevent an escape when your team is mopping up.

Level 10 Nano Boost
Throw this on a DPS, throw this on a tank, hell, throw it on that guy who's wrecking face!

Level 13 Speed Serum
This helps your team catch stragglers, or get out of a fight faster.

Level 16 Contact Healing
By now you should have the Grenade Calibration quest long finished, so you have a huge AoE for your grenades, and what better to enhance that with than more healing!

Level 20 Somnolent Doses
This is where everything ties together. This talent, enhanced with the doses from Overdose and Shrike means you can knock the enemy team out super fast. I love using it on someone just as they pop their Ult, so they get knocked out by Sleep Dart, then a couple more doses from auto attack, and boom, they're out cold again. This can really break a team push late game.

So that's my guide! Let me know what you think!