I'd thought that Ana's nano shoots a projectile which applies the nano boost buff. And the OW wiki backs that belief up.
Nano Boost is a non-hitscan projectile that cannot miss and cannot be blocked. However, if the target dies before the projectile reaches them, Nano Boost gets consumed and wasted. sauce
However I just went and watched a replay, and that's not what I actually saw. Watching it at 0.25x speed, and pausing/rewinding constantly, here are the actual series of events that I observed.
- Ana raises her arm
- Monke gets healed and starts glowing red (Ana was on red team in replay)
- A red laser beam appears from Ana




