According to PW Insider, Naomi is currently scheduled to make her WWE return during this Sunday's Royal Rumble PPV. It's said that she will be sent to the SmackDown brand following the event as that's obviously where The Usos, and her husband, currently are.
She's been out of action since last July and her last televised appearance was a win over Sarah Logan on an episode of Main Event. In late September, she mention having health and family issues and both she and The Usos were left out of last year's WWE Draft because the creative team had no plans for them at the time.
Noami was rumoured to make her return back in November but that didn't happen and with twenty five open spots in the Royal Rumble match, it makes sense for her to make a "surprise" return there.
As always, stay tuned for updates!