Makar, who had 12 of Colorado's 51 shots, won it with a wrist shot from the edge of the face-off circle to give the Avalanche a 2-0 lead in the best-of-7 series.
"Give credit to their goalie (Connor Ingram), he played well," Makar said. "He was making the saves that he needed to make for them, and the one at the end there, just got through] traffic. I tried to just throw it low and luckily went in, but it was overall just a good effort, I feel like, by the guys getting everything to the net."
Nathan MacKinnon also scored, and Darcy Kuemper made 25 saves for Colorado, the No. 1 seed in the West.
Game 3 will be played at Nashville on Saturday.
"My belief is that we just had to keep doing what we were doing and we'd find a way to win the hockey game," Avalanche coach Jared Bednar said. "I thought 'Kuemps' did an amazing job of staying in the game with the way we were limiting shots, especially in the second half of the game, and staying sharp. He ends up making some big saves, a couple in the third and another couple in overtime, for sure, that give us a chance to win that game."
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Ingram made 49 saves in his first NHL playoff start, and Yakov Trenin scored for the Predators, the second wild card in the West. The 25-year-old rookie got the start after he made 30 saves in relief of David Rittich in a 7-2 loss in Game 1 on Monday.
"I think [Makar's shot] was the first one all game I didn't get my eyes on before it got to me, and that's what happens," Ingram said.