[4] Nichols was added to the national team in March and was selected to represent the United States at the City of Jesolo Trophy and the Germany-Romania-USA Friendly.

[5] At the City of Jesolo Trophy, she finished first with the team and sixth in the all-around, and won a silver medal on the floor exercise.

At the U.S. Classic, Nichols finished sixth in the all-around, eleventh on uneven bars, eighth on balance beam, and fifth on floor exercise.

Nichols helped the United States finish first at the Pan American Gymnastics Championships in Mississauga, Canada, and placed third in the all-around competition with a score of 55.500.

At the 2015 World Artistic Gymnastics Championships, Nichols competed on vault, balance beam, and floor exercise in the preliminary round.

"[17] A month later, Nichols tore her meniscus while training her Amanar vault and had to withdraw from the 2016 Pacific Rim Gymnastics Championships in Seattle.

There, she finished sixth in the all-around, fifth on vault, ninth on uneven bars, eighth on balance beam, and fourth on floor exercise.

Károlyi explained that she was not chosen even as an alternate because while she had performed well at the Trials, her score was not in the top 3 on any event which made her of no possible benefit in a team final format.

A few days after the conclusion of the Olympic Trials on July 13, 2016, Nichols announced her retirement from elite gymnastics via Instagram and interview,[20] and said she was taking time to rest before starting her NCAA career at the University of Oklahoma in August.

[22] In the 2016–2017 season, as a freshman majoring in health and exercise science, she made the competitive lineup on all four events and scored at least one perfect 10 on each.

[23] She finished the regular season in first place in the all-around, ahead of Utah's MyKayla Skinner; second on vault, behind Ashleigh Gnat of LSU; second on uneven bars, behind Kyla Ross of UCLA; tied for second on balance beam with Oklahoma teammate Chayse Capps, behind UCLA's Katelyn Ohashi; and tied for first on floor exercise with Skinner.

[24] At the 2017 NCAA Championships, she had a surprising fall on balance beam, her first major mistake of the entire season, missing out on the all-around podium despite being favored to win.

At the first home meet of the season, against Iowa State and Texas Woman's, Nichols won the uneven bars, balance beam, and all-around titles.

[26] She followed up this remarkable performance by repeating her perfect 10 on balance beam at the following week's dual meet versus North Carolina.

[30] The Sooners finished their home stretch with a quad meet against Arkansas, Arizona State, and Denver, where Nichols earned titles on balance beam and in the all-around.

At Alabama, Nichols earned a perfect 10 on vault and also won titles on uneven bars, balance beam, and in the all-around.

[32] Competing at Texas Woman's just two days later, she earned a perfect 10 on floor exercise, as well as titles on vault, balance beam (tied with teammates Natalie Brown and Bre Showers) and in the all-around.

She also shared the floor exercise title with teammates Dowell and Webb, Maddie Karr of Denver, and Haylee Young of Iowa State.

[34] At regionals in Minneapolis, Nichols helped the Sooners qualify to the national championships by scoring a perfect 10 on balance beam.

“It was my hard work paying off, and I'm so happy I could do it for my team.”[35] At the national championships in St. Louis, Nichols and the Sooners competed against Utah, Florida, Washington, California, and Kentucky in Semifinal II.

[36] During the Super Six finals, Nichols contributed a 9.9375 on vault, a 9.9625 on uneven bars, a 9.9125 on balance beam, and a 9.9625 on floor exercise, but Oklahoma ultimately finished second to UCLA by only .0375.

[41] She spent the remainder of the season only competing on two events, uneven bars and balance beam, hoping to return to the all-around in the post-season.

[56] Nichols graduated from Roseville Area High School in 2016[57] and from University of Oklahoma with a bachelor's degree in communications and business and a Masters of Education in Intercollegiate Athletics Administration in 2022.

[58][59] In January 2018, Nichols came forward as one of the many victims sexually abused by former USA Gymnastics doctor Larry Nassar, starting when she was 15.

[63] In a column published March 27, 2020, Nichols stated that she would work as a student coach for the Sooners while completing her bachelor's degree and also indicated interest in sports broadcasting and writing a book.