I think historically in Madden, the Nickel CB has always played like Charles Woodson does in real life, regardless of who it is. CBs in general in Madden are too good against the run and they are the force player in most defensive plays in Madden.
If you're running a toss or power play to the right in Madden, is it your preference to have a WR on the play side (right) or the weak side (left) ? I think historically in Madden most would say keep the WR on the weak side (unless the D is in zone where the CB will be left unblocked). This is because the CBs are way too important in the running game where the OLB and SS should be utilized as the force player more often. In other words, it's way too easy to kick runs outside unless there is a CB in the area.