Romanov made it 2-0 with a point shot that beat Rittich high glove side at 4:22 of the second period.
"I thought our commitment level and our discipline, too, was very good tonight," Lambert said. "We pushed forward and we did a real good job of establishing our game."
Nelson extended it to 3-0 at 18:41 with a shot from the high slot after he put the puck between the skates of Kyle Connor to get open.
"It was a good play," Nelson said. "We weathered a little pressure in the D-zone. It was a nice play by Zach (Parise), got past (Jets defenseman Neal) Pionk and I cut to the middle."
Pelech scored into an empty net at 17:59 of the third period for the 4-0 final.
"We gotta figure it out," Jets forward Pierre-Luc Dubois said. "I, personally, individually, I don't think it's one guy that has the answer in here. It's everybody together. It's the coaching staff. We all gotta figure it out. You guys see it, we're not playing good hockey right now. But at the same time, we can turn this around and turn it into a positive. We just got to get going. Time's running out."
NOTES: Varlamov's 38th NHL shutout was his 13th with the Islanders through four seasons. … The Islanders won their seventh straight against the Jets dating to March 28, 2019. It is New York's longest active winning streak against one opponent. … Horvat set a NHL career high with 62 points (36 goals, 26 assists). He has five goals in 11 games since being acquired by the Islanders in a trade with the Vancouver Canucks on Jan. 30. … Nelson has 21 points (12 goals, 9 assists) in his past 17 games. His 60 points (27 goals, 33 assists) are an NHL career high. Nelson is the first Islanders player with a 60-point season since Mathew Barzal (19-41-60) in 2019-20. … The Jets were held to one shot in the first period for the first time since they relocated from Atlanta for the 2011-2012 season. Winnipeg's second shot on goal came at 5:15 of the second period.