Born in Madison, Wisconsin, and raised in Verona, Schmaltz grew up playing hockey in his basement with his brother Jordan and sister Kylie.

During the Coyotes' 2021–22 roster overhaul, Schmaltz was part of the core group of players they chose to build around, and that March he set a franchise record with seven points in one game.

[1] His father Mike owns a series of fitness centers, while his mother Lisa is a radiologist for the UW Health University Hospital.

[2] Their family home in Verona, Wisconsin, had a makeshift roller hockey rink in the basement, with Nick's older brother Jordan and younger sister Kylie teaming up to play against him.

He joined the team as an affiliate player for the final 11 games of the 2011–12 regular season,[5] contributing one postseason goal and three assists as the Gamblers took the 2012 Clark Cup.

[9] He began his freshman season on a hot streak, named the National Collegiate Hockey Conference (NCHC) Rookie of the Month for October after leading all freshmen with six points in as many games.

[10] On February 23, 2015, Schmaltz was named the NCHC Rookie of the Week for assisting on two goals of the Fighting Hawks' 3–0 shutout win over Western Michigan.

[13] North Dakota played in the 2015 NCAA Division I Men's Ice Hockey Tournament, where they were eliminated in the Frozen Four by Jack Eichel and Boston University.

[30] His offensive output was negligible from then on, with only one goal and three assists in 26 games, and on December 4, 2016, the Blackhawks sent a slumping Schmaltz to their American Hockey League (AHL) affiliate, the Rockford IceHogs.

[32] Playing on the top offensive line with Panik and Jonathan Toews, Schmaltz's performance improved during the second half of the season,[33][34] and he finished with six goals and 28 points in 61 regular-season NHL games.

[40] Schmaltz's major development over the course of his sophomore season was to gain confidence with the puck rather than passing to more experienced players like Kane and Toews.

[43] He did not score until the eighth game of the 2018–19 season, shortly after head coach Joel Quenneville pushed Schmaltz to the left wing and put Anisimov at center.

[48] Schmaltz later revealed that his knee had been bothering him for a long period of time and that he could not name a specific moment that had caused the injury, which required a season-ending surgery.

[59] Head coach Rick Tocchet nicknamed the trio the "Short Leash line" for their presumed defensive liabilities despite their offensive production.

[61] On March 27, the NHL Department of Player Safety awarded Schmaltz a $5,000 fine for dangerously pushing San Jose Sharks defenseman Radim Simek into the boards the day prior.

[62] On May 3, with three regular-season games left to play for the Coyotes, Schmaltz was hit in the head during pregame warmups by a puck that bounced off the crossbar of the goal net.

Unexpectedly playing without him, the Coyotes lost 3–2 to the Los Angeles Kings that night,[64] a loss which mathematically eliminated them from the 2021 Stanley Cup playoffs.

[67] The Coyotes underwent a major roster overhaul prior to the 2021–22 season, with Schmaltz part of a core group of young players that the team wished to build around.

[77] Later that year, Schmaltz was part of the gold medal-winning United States team at the 2013 World Junior A Challenge in Yarmouth, Nova Scotia.

[82] Following his first season of professional hockey, Schmaltz and teammate Trevor van Riemsdyk represented the United States senior team at the 2017 IIHF World Championship.

[86] Outside of his immediate family, Schmaltz's cousin Jake began playing college hockey for North Dakota in 2021 as a Boston Bruins prospect.