This can be considered Black's main line.
1. g1f3  1... d7d5  2. g2g3  2... g8f6  3. f1g2  3... e7e6  4. e1g1  4... f8e7  5. d2d3 Nepomniachtchi chose the  King's Indian Attack for the decisive game. 5... e8g8  6. b1d2  6... c7c5  7. e2e4 