The FAQ thread for BfA has just thrown up the best official answer to a rules query I have ever read. GW take note...
the gamer wrote:2. I know cou cannot target a Nano counter normally, but could you do it with a rad grenade? (Since this grenade only effects nano counters now)? Otherwise the strain player can simply keep his/her Nano away from his models and only rush it in, when needed for evolution etc..
Rob, the rules guy wrote:
You cannot target nano counters, they are not models. You cannot do it with a rad grenade, a turnip, or harsh language. Trust me on the harsh language, it would be like swearing at air, really evil air. Consider that Canon.