Quite a vigorous way to play it!  Nepomniachtchi wants to spoil his opponent's castling at the first  possible moment. Error reading move: Bc3 So is not afraid to castle into  it. The first clash is over. Both sides are ready to attack the opponent's king. Consistent. Blunder alert! Threatening a capture on c4, either with  or without the trade on g3. In order to defend the c4 pawn.
1. b2b3  1... b7b6  2. c2c4  2... b8c6  3. e2e3 