She announced her decision Thursday in an email message to the chamber's board.
"I just felt like maybe it was time for me to move on," she said in an interview. "I love working for the chamber, honest to goodness. It's the best job in town."
Nobis, 65, plans to stay on until March 29. She hopes the board will be able to hire a replacement by then.
"I would like to have the opportunity to do some training with the new person before I leave," she said.
Nobis was hired on July 21, 2008, to lead the Chamber. She presided over a period of growth for the chamber despite economic malaise nationally and in the San Juan Basin.
"She's made quite a contribution, and can take credit for a lot of progress made at the Chamber," said John Byrom, a Chamber board member and president and CEO of oil and gas producer D.J. Simmons Inc. "At the same time, she's managed to keep the Chamber under solid financial footing and that's happened under challenging economic conditions."
Nobis said she wants to seek another job in the Farmington area.
"I've learned a lot, I've had incredible friends and I've been blessed to have had the position," she said.
A former hair stylist, salon owner and journalist, Nobis has filled many roles since coming to San Juan County. She worked as a reporter and editor at The Daily Times and as a radio news director.
She also served as a San Juan County public information officer.
The chamber advocates for local businesses and hosts events. The nonprofit organization has an annual budget of about $280,000. The Chamber has approximately 830 members, 75 of which were added in 2012.
Byrom said the board would look for an orderly transition.
"I don't see any reason why we would be holding off," he said. "I think the organization, the staff down there, is good and knows what to do, and the board members are active enough I think the organization will perform well during the transition."
Byrom said he would miss Nobis' "personal touch."
"She always makes an effort to come greet people in the crowd in person, and has a sincere way about her," he said.