Sure .That's why we need large amounts of flexible storage to be built. It's purpose will be to fill the gaps in the rewewable intermittency.
For quite a long time existing coal and gas will continue to used as backup, albeit in reducing amounts over time as it is displaced by more renewable generation and storage. That way we can extract the maximum value out of the old investment rather than spend new money on something temporary.
Backup machines don't produce any emissions if they are not running e.g gas fired peakers.
Nuclear is very, very expensive and takes a very long time to build. If we were to start on one today in Australia it would be over a decade before it was finished based on overseas projects. And that's if you could find somewhere to put it on the east coast. Good luck with that ! Of course to build nuclear power stations you need a nuclear industry which we don't have. Another roadblock and large expense. Not to mention the small issue of waste that will outlast humans.
Or, you could manage the existing fossil fleet well and progressively integrate renewables plus storage which are cheaper anyway ( LCOE ) and produce no emissions and no waste.
It's not that hard to work out which is the smart way to go.
