It won't solve your gnat problems. For gnats :

Buy
a package of "Mosquito dunks" at the garden center. Put one
quarter of one in your watering can. This will kill the larvae in the
soil and stop future generations. It is all natural and safe. Use
sticky traps and manually kill the adults.

Gnats (not "nats") are too small to set off the vft's trigger hairs. An alternative to mosquito dunks would be to try Drosera, Pinguicula, and/or Utricularia. The first two will capture gnats while the underground traps of the third may take out some of the larvae.