I didn't see MNF, so I can't comment upon what they said, but if they did say as you did, then they must be suffering from underdone Turducken.
No AFC match can effect the NFC. The Pit/Bal game has ramifications on the AFC picture, on who wins the AFC North. Cinci needs a loss by Bal and a win against Cle.
NFC is as you state. Min or GB to win the NFC North, Min has the lead, and the one that doesn't win needs either to have Sea lose or Dal win, as Sea has the better Strength of Victory.
Of course, MNF cannot be blamed too much if they do get it wrong, NFL playoff tie breaking system is more confusing than Feng Shui.
NFL Playoff Breakdown