Nano Mech is a Science-class mech in Into the Breach.
Team
The mech is available as part of the Hazardous Mechs squad.
Strategy
Repairing mechs with the Viscera Nanobots passive happens after all damage calculations are rolled, with this value having a floor of 0 HP (i.e., can't be a negative number), so a mech that hits 0HP with a self-damage weapon that kills its target will be revived. Thus, high power secondary weapons that deal self-damage to the mech are great additions to the Hazardous Mechs; in particular Self-Destruct, as it will revive the Mech while it instantly destroys any threats.
The Nano Mech's main weapon A.C.I.D. Projector acts much like the Cannon Mech's Taurus Cannon by pushing its target, difference being that it applies A.C.I.D. on the target rather than damaging it. This is great utility to have by granting an increase in the damage output of the squad the Nano Mech is placed it.
If using the Nano Mech in a Custom Squad, it is best paired with Mechs that have direct damage output, so they can take advantage of the A.C.I.D. status to kill enemies without relying on powering damage upgrades quite as much. The Viscera Nanobots passive is a lot more situational on Custom Squads though, so if it's not needed, it should be sold for Reputation eventually; particularly when it makes the difference to purchase an important side weapon or an additional Reactor Core.