Against Nimzo Indian defense white plays 4.e3 white postponed e4 for while and white will develop his king side pieces and castles after completing these task white will think of playing e4.
White’s Strategy in Nimzo Indian e3
After castling white will resolve his blocked queen’s bishop by playing e4 or other way he has to active his dark bishop. If black retreat his bishop then white can play e4 easily. if Black captures on c4 and doubles the pawns then White should take care of his weakened pawn structure before activating his bishop pair.
Black’s Strategy in Nimzo Indian e3
Black must attack in the center with his pawns and pieces. The Nimzo-Indian Defense is a rich opening and Black has lot of plans. For example he can play an early …c7-c5 and …d7-d5, exchange these off and leave White with easy development but an isolated d-pawn. Alternatively, he can play a quick …c7-c5, …Bb4xc3, …d7-d6 and …e6-e5, (Hdbner variation) where he gladly gives up his dark-squared bishop and plays for a rock-solid center which White’s bishops may have difficulty in breaching.
TIP: The Nimzo-Indian Defense is an good if your strengths are strategic rather than tactical.