Nuno Espirito Santo's side are in fine form in the Championship this term and currently sit four points clear at the top of the table, just three shy of the 50-point mark with three games to go until the halfway point of the campaign.
Having recruited heavily over the summer, the Midlands outfit are not expected to do much business in January but have earmarked a top-quality striker as their top priority as they look to make certain of promotion in the second half of the campaign.
According to The Mirror, Nuno tried and failed with a loan move for Okaka over the summer but could move again next month after the Italian fell down the pecking order at Vicarage Road.
Hornets manager Marco Silva has played Okaka just twice this season and is said to be keen to offload the striker in January to raise funds for other spending.
Okaka joined Watford from Anderlecht in a £10m deal in 2016 and still has three and a half years remaining on his contract.