Just my opinion, but my feeling is that Nick died fairly recently. The report clearly says he a man's body was found on the beach, not that it was washed up onto the beach. It also seems, as has been pointed out above, that the identification was fairly swift and it was clear from the outset it was the body of a male. I'd think that if a body had been in the water for one month, it would be a different kettle of fish.
Hard to imagine what he would have been doing, where, how and why during the time he was missing since 26 Nov. Thinking back over what has been reported, there are a number of milestones that are kind of spaced out during that time.
On 26 Nov he goes missing and sends that text message to this wife, leaves work early and leaves his work satchel on his work desk. Seems like he did not have the plan to return, as that wasn't customary practice for him.
On 9 December there were a number of transactions with his bank accounts. Still unclear whether that was via ATM as originally reported or via some other means.
On 10 December his car and phone were found abandoned in Cremorne. Parking tickets date back to about one week. That would mean early December. That means there is a possibility he may have still been driving his car for a few days from the time he went missing to when the first parking ticket was written. On the other hand, it could just be that parking inspectors did not visit that street until early December.
There seems to be a time lapse from when he originally went missing and when this was first reported in the media. I dont think media reports came out until 9 or 10 December, around the same time as his Missing Person facebook was set up. That was a bit strange. I wonder whether family or police suspected he might have just taken time out and thought he would reappear and when that did not happen for two weeks, then they went out to the media?
Then there were all these reported sightings of him around Sydney and elsewhere - hard to know whether it really was him or not.
And then he was found on the beach on 29 December.
What a pity if he was alive for a number of weeks and was not found earlier.