In a statement on its website, Sigma has said that the current firmware of its Nikon-fit interchangeable lenses 'may not work properly with the Nikon D5300's OS and Live View Auto Focus functions'.
Though it hasn't released specific details, Sigma has said that the problem occurs specifically with Nikon-fit interchangable lenses that incorporatean internal motor.
Sigma will be releasing a free firmware update tomorrow (November 20) that it says should correct the problem. You can contact your nearest Sigma dealer in order to receive the update; Sigma provides a full list here.
See Sigma's website for the full statement.