Nick Holden gave the Golden Knights a 1-0 lead at 18:44 of the first period.
Karlsson, acquired from the Ottawa Senators on Sept. 13, tied it 1-1 with a power-play goal 5:41 into the second.
Vegas responded with three goals in a span of 7:31, including shorthanded goals from Nosek (9:39) and Pacioretty (17:10). Reilly Smith gave the Golden Knights a 3-1 lead at 11:25.
Nosek made it 5-1 with his second shorthanded goal 1:42 into the third period.
Kevin Labanc got the Sharks within 5-2 with a power-play goal at 16:28 of the third.