MELBOURNE – A nervous Naomi Osaka overcame a second set wobble to make a winning return Tuesday in her first match since taking an indefinite break after a tearful US Open exit in September. The four-time Grand Slam champion, who has slid to 13 in the rankings, admitted after her third-round defeat at Flushing Meadow that she was “dealing with some stuff” emotionally. She had mostly laid low since before flying into Melbourne last week to prepare for her Australian Open defense. The Japanese superstar took the first step towards that goal at the Melbourne Summer Set tournament, but was nowhere…