In the Gameplanning menu, neither the Def Plays or Scout Defense options shows the personnel on the field for that particular play. We can see the play name and both the DB/LB assignments, but not the defensive formation.
However, the individual player page does list the defensive formation on the line after the play name which makes it easier to identify personnel. My suggestion is to add the formations to the Gameplanning menu so I can align my formations (Base,Nickel, Dime, etc.) to better match my opponents style of play.