Ex-Broncos QB Chad Kelly plead NOT GUILTY to felony criminal trespassing stemming from allegations he broke into a Colorado home after Von Miller's Halloween party ... only to be chased out by a person beating him with a vacuum cleaner tube.
The 24-year-old appeared in court in Arapahoe County, Colorado on Monday to enter the plea. This is a huge deal for Kelly -- because if convicted, he faces up to 3 years in prison and a $100,000 fine.
The trouble for Kelly started after he left Von Miller's Halloween party on October 22nd .