It was Nabokov's third shutout this season for the Islanders, who moved within one point of eighth place in the Eastern Conference despite having won only six of 19 home games this season.
After losing their three previous home games by faltering in the third period, the Islanders shut down the Panthers, who have the NHL's worst record at 9-18-6.
MacDonald scored his second goal of the season at 6:05 of the first period on the power play.
John Tavares scored his team-leading 19th goal, an empty-netter with 31 seconds left. Casey Cizikas added an empty net score with 13 seconds remaining.
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