There will be no further comment from CA until a review of events has been completed.
The controversy over Nixon's performance comes against an antagonistic backdrop so far in this winter's Ashes, which has included an outbreak of 'sledging' in England's first-Test defeat at the Gabba last week and a frosty, partisan reception for the tourists from media and home crowds alike.
Ian Bell, leading England in Alice Springs in the absence of the rested Alastair Cook, appeared mystified by the turn of events.
The England and Wales Cricket Board made no complaint about Nixon, and was unaware of his sacking until told by the hosts.
At his post-match press conference, Bell said: "We weren't aware of it, didn't know anything about it.
"Until now ... I don't think any of the team were. We were focused on the cricket.
"You could hear him through the game, but hadn't heard he'd been sacked."