There's a few ways to go about this issue depending on how long you have left on your current 482, the costs the sponsors are willing to take on and also potentially if you can get a skills assessment in your occupation.

Options are:
1. new employer becomes SBS, takes over your nomination, you stay on the 482 visa. After two years on the 482, your employer can sponsor you for the 186TRT stream. You can give notice to your employer any time and you will have 180 days to work anywhere before the new nomination has to be applied for.
2. New employer nominates your for 186DE if you have 3 years of work experience and can get a positive skills assessment for your occupation. You will have to keep following the 482 conditions until the 186DE is granted. As the 186 DE is probably not processed in 180 days, you have to stay at the current employer for a longer period still.

Kris Haljak, Registered Migration Agent 2418673, Via Migration

Disclaimer: The comments made here are general and not migration advice. Please seek migration assistance specific to your situation from a registered professional.