The 27-year-old forward could have become an unrestricted free agent on Wednesday.
"Signing 'Val' to a long-term deal was a top priority for us this offseason as he would have been one of the most sought-after forwards on the open market," Avalanche president of hockey operations Joe Sakic said. "Val is a big, strong, fast, tenacious winger who is relentless on the puck. He can play on the first line with our top guys, you can move him up and down the lineup. He plays power play, penalty kill, any situation you need him to.
"He works hard off the ice as well in the gym and is a humble person and great teammate. He is such an important player in our lineup and a huge reason why we won the Stanley Cup."
Nichushkin set NHL career highs in goals (25), assists (27) and points (52) in 62 games this season. He had 15 points (nine goals, six assists) in 20 Stanley Cup Playoff games to help Colorado win the championship for the first time since 2001.
Selected by the Dallas Stars in the first round (No. 10) of the 2013 NHL Draft, Nichushkin has 174 points (71 goals, 103 assists) in 405 regular-season games for the Avalanche and Stars, and 24 points (13 goals, 11 assists) in 62 playoff games.
Colorado still has several players who can become unrestricted free agents Wednesday, including forwards Andre Burakovsky, Nico Sturm and Darren Helm, and defensemen Josh Manson, Jack Johnson and Ryan Murray.
