Jim Molan is currently ahead on the NSW Senate ticket and might well get in.
It is rumoured that the 72 year old will announce his retirement after being sworn in.
What happens then....??
When a casual vacancy occurs in the Senate, on the resignation or death of a senator, a new senator is appointed by the parliament of the state which the former senator represented. If the state or territory parliament is not sitting, an appointment can be made by the Governor of the state ( or in the case of an Australian Capital Territory senator, the Governor-General, or the Administrator in the case of the Northern Territory) and the appointment is confirmed by the parliament when next it assembles.
In order that the Senate continue to preserve the representation of parties in the Senate as determined by the electors, the new senator must be of the same political party or group as the senator he is replacing. It is a matter of contention whether this means that the appointee must be the nominee of the political party or whether it suffices that he or she is a member of that party. source
This means that, should Andrew Constance fail in his bid for Gilmore as a Member of Parliament he might well be a shoe-in to fill the Senate vacancy. The test would be to see if he still has any support within the State Liberal party having resigned mid term, and by his reputation that has taken a toll during the 2022 election by way of association with Scott Morrison.