SAN FRANCISCO 49ers
San Francisco clinches West Division title:
1) SF win + SEA loss or tie
2) SF tie + SEA loss
GREEN BAY Packers
Green Bay clinches a playoff spot:
1) GB win + DAL loss or tie + ATL loss
2) GB win + DAL loss or tie + NO loss
3) GB win + ATL loss + NYG loss or tie
The Niners situation is fairly obvious as they need to win on overall record at this point since they can't clinch either H2H, division record, common games or conf record tiebreakers.
As for GB, that's a little more difficult since so many teams involved have to play each other still. NYG and DAL still have 2 games left H2H. NO plays nearly everyone involved as they play NYG this week and still have DET and ATL on their remaining schedule.
A GB win gets Packers to 11-0 and 11-5 at worst. If Saints or Falcons get to five losses, they cannot get in over Packers. Neither team can use DET or CHI to get in over GB either since both of those teams would lose a tiebreaker to GB at 11-5. At 11-5, both DET and CHI would have to win certain games to tie GB in the division at 4-2 and that would lead to GB beating both teams on common opponents. Currently GB leads DET in common games at 9-0 vs. 6-2 and leads CHI 8-0 vs. 6-2 and GB would go to 9-0 in CHI scenario with win at DET this week.
A DAL loss or tie this week is one key as that would force DAL to beat NYG twice to stay at pace with GB and would only leave the NFC East champion and no Wild Card contenders. If you combine the DAL loss/tie with either an ATL loss (ATL lost to GB H2H and would have inferior conf record and can't use anyone to jump GB in multi-team tiebreaker) or a NO loss (loss would require NO to beat either DET or ATL to stay at pace with GB), that gets GB a playoff spot.
Since GB plays NYG wk 13, an NYG loss/tie on its own is not as key since the Giants could beat GB H2H in tiebreaker. However, for that NYG-GB H2H to come into play, NYG would have to sweep DAL thus eliminating the Cowboys from this tiebreaker and gives NYG the East title. When you combine that with an ATL loss it gets GB to a point where only one of DET or CHI could be Wild Card in front of them (the other would be the division winner).
If you don't factor in potential ties (especially for NO games down the road), GB really only needs a win and either a DAL loss or NYG loss to get into the playoffs. However, ties are possible and must be factored in to actually CLINCH a playoff spot with no room for error.
Hope that helps...Joe