You are eligible for Subclass 408 if you hold a substantive visa with work rights and have a valid job offer unless you have a job offer from a Commonwealth-funded aged care service. You must apply within 90 days of your current visa expiry, i.e you cannot apply for Subclass 408 visa if you have more than 90 days to your current visa expiry.
If you need Immigration assistance get in touch by making an appointment for a phone/video consultation or ask for a written consultation.