Everyone in the NFC North is nominally a rival of the Green Bay Packers. That’s the whole point of the divisional structure. You set teams up to see each other twice a year, add in a little regionalism, and sooner or later you’re going to manufacture some shared history.
The NFC North is fairly unique in this aspect because, in addition to those other factors, all three of the teams in the division had existing relationships long before the realignment that created the North, dating back to the NFC Central era and beyond. Nobody really needs an update on the Packers/Bears rivalry, there’s always been plenty of heat in the Packers’ relationship with the Vikings, and the Lions were a thorn in the side of the Lombardi-era Packers.