Ex-NFL DB Nick Collins -- Aaron Rodgers' AND Brett Favre's former teammate in Green Bay -- says with one more ring ... Rodgers will be the best Packer QB to ever live.
"If he wins the Super Bowl this year, you would have to say he's the greatest," the three-time Pro Bowl safety tells TMZ Sports.
It's high praise ... considering both Bart Starr and Favre are already in the Pro Football Hall of Fame -- but that's how high Nick is on Aaron -- especially after his comeback win over the Bears on Sunday.
"To come back out there and just dominate the second half ... on one leg?!" Collins says. "Come on now, you have to put that up there."
By the way, Collins was drafted in the same class as Rodgers -- and has already been inducted into the Packers' Hall of Fame.
Collins compared Rodgers' performance to Michael Jordan's flu game ... saying other than Rodgers' lone Super Bowl win, it was the best night of the quarterback's career.
As for Rodgers' place on the QB rankings OUTSIDE of Green Bay ... Collins says it'll take a whole lot more than just one more Super Bowl to get him to the top of THAT list.