"___ currently holds a valid visa for travel to Australia. If a visa is granted as a result of this application it will replace the visa currently held by the applicant. The applicant should check their current visa details and conditions via Visa Entitlement Verification Online (VEVO) on our website, before continuing with this application. This will help the applicant to confirm that the visa being applied for is more beneficial than the visa currently held"
As a general rule, you can only hold only one Australian visa at a time. While you can apply for a Visitor (subclass 600) visa while you are holding a Temporary Skill Shortage (subclass 482) visa, if your application is approved, your Visitor visa will "overwrite" your Temporary Skill Shortage visa (see subsection 82(2) of the Migration Act 1959), and you will lose your work rights.