Originally from the Bay Area in California, Arellano was a goalkeeper on championship teams at Evergreen Valley College in San Jose, and at NCAA DII Notre Dame de Namur University in Belmont (CA). He signed a professional contract with Real San Jose of the National Premier Soccer League (NPSL), playing from 2007-2010. Arellano was a two-time recipient of the NPSL National All-Star Award for goalkeeping.

Arellano has 15 years of coaching experience, starting with Real San Jose, where he served in many roles including head coach, and director of youth programs with the organization. He returned to Evergreen Valley College to coach keepers in 2009 and was the head coach at Overfelt High School (CA) in 2010 and '11. 

He moved to Hawaii and worked with the Hawaii Rush and Hawaii Surf soccer clubs before moving to Washington. He's coached with the Northwest Nationals, Greater Seattle Surf, Washington EPD, and Seattle United organizations. He was with Seattle United for seven years and served as the West Region Goalkeepers Director and head coach. Arellano joined the Washington Rush organization in 2024 and holds his USSF C coaching license.

Arellano was voted as the Seattle Youth Soccer Association's (SYSA) Competitive Girls Coach of the Year in 2020.

Arellano has a bachelor's degree in psychology from Chaminade University and currently works in special education at Nathan Hale High School in Seattle. He recently obtained his master's degree in Teaching with an endorsement in special education from Seattle Pacific University.

"I'm excited to reboot this program. We will succeed on the field, in the classroom, and in the community," Arellano said.

"Above all, Nico is a great person. He's a genuine guy who really cares. He's the type of coach you'd want your daughter to play for. It became clear he was the right fit for our department," said Edmonds athletic director Spencer Stark. "Nico has a big challenge ahead of him and as an athletic administration we are prepared to support him."

In 2023 midfielder Avery Libed was selected to the NWAC North Region 1st-Team. Jaiden Irons, Alysah Forde-Nihipali, and Genavieve Stettler were all named as Honorable Mention.

This past season (2024) Yetlanezi Yaxoak-Keiper was named to the NWAC North Region 1st-Team and freshmen Saige Palazzotto and Alyssa Castillo were tabbed to the 2nd-Team.