Awww... No team? Un-Sim?
Super Bowl XXVII - 4th and Goal - Cowboys use Nickel against Bills base formation. Thomas Everett intercepts Jim Kelly in the end zone.
Not so Un-Sim now is it?
That said, we agree on something. Anyone who knows what they are doing would have a field day against this defense - but matchups would only be 1/3 of the equation. The other 2/3 are often ignored by Madden players who view 'sim' in concrete terms. Usually their assessment of SIM is personnel heavy, but football strategy has 3 parts that fit together and are equally important: Personnel, position, and tempo.
If a person has committed ample thought to how to use his personnel, positioning, and timing to accomplish his overall goals - HE CAN WIN against people that only look at 1/3 of the overall picture.
Often we see people, no offense to them, who view macth ups as the only important strategic part of football. Often they are also the quickest to leap to the 'unsim' conclusions about strategies that are heavy on the position and tempo fronts.
Apparently the OP has discovered a method that works to cover the typical weaknesses of the man defense using nickel personnel. While his defense has a weakness somewhere, it's not where it seems it should be. I'll guess that most of his opponents get discouraged in the run game after getting stopped early - then they play right into his hands.
Personally, I'd run the ball at least 25-30 times and test his discipline. If I ended up with 20 yards for the game, I'd probably still end up winning because of the type of attention he'd be forced to pay to the run game. Since I use all types of run blocking, I'd find something to keep him off balance and work my passing game in from there...
If my run game didn't get started, I'd punt as needed and return the favor by imitating my opponent's defense to see how he adjusted to it. Then I'd use his adjustments against him when he was on defense again.
The wildcard will always be the USER. The more skilled the user, the more likely he can pull off using nickel packages long term against base sets. Unskilled users will either abandon their plan too early - or stick with it too long when it's getting beaten.
Later