THE Nimzo Larsen begins 1.Nf3 followed by 2.b3. 1.b3 is LArsens penning and very unsound.
Since I answer 1.Nf3 with 1...Nc6, I am very happy if White insists on playing 2 b3 there.
2. d4 and it's a Queen pawn opening with your black knight blocking your c-pawn which sometimes is not a good thing.
"[1 b3, 1 b4 and 1 f4] have interesting unique connotations and can even be recommended as an occasional weapon for White. Although the main lines (1 e4, 1 d4 and 1 c4) remain the real McCoys …" - GM Gabor Kallai (1997)