When the Romulans first arrived on Chetzia they were exposed to a deadly virus and in response they genetically modified a species of plant to kill off the virus. The virus was successfully destroyed, however the genetically modified plant has now begun to take over the planet.
In 2377 Chetzia III was one of the first planets to fall under Warden control. The Wardens planned to have the USS Leyte Gulf, also under their control, delivered to the planet, however the crew of the USS Incursion intercepted the Leyte Gulf first and then came to Chetzia III themselves to try and gain intelligence on the Wardens.
Some time later, following the Borg's destruction of Warden facilities on Romulus, the Wardens set up extensive facilities on Chetzia, however once again the crew of the Incursion were following in the Wardens' footsteps and soon arrived with antimatter chargers to destroy the base. (ST video game: Away Team)