Redesign Nano Sabre or redesign Chainsaw.
The Nano-Sabre is redundant in its current functionality, because the chainsaw can do what the sabre does and more.
Killing a hostile mob with the Nano-Sabre and the chainsaw both take two strikes. The chainsaw doesn't need to be turned on/off and also cuts down wood.
Due to that the Nano-Sabre isn't useful.
To fix this either make the Nano-Sabre a one hit killer (you still have to switch it on and off) or reduce the damage of the chainsaw, so it takes three hits to drop a hostile mob.
No change to existing recepies necessary.
Liebe Grüße aus Südhessen