The Kerala-based Grandmaster remained unbeaten in the nine-round tournament.
So took home the first prize of $200,000, while Keralite Nihal was richer by $100,000.
The 16-year-old has attained two of the three requisite norms to become an IM.
Arjun also remained unbeaten through the nine rounds and finished half-a-point ahead of Uzbekistan's Javokhir Sindarov.
The Indian GM shocked super GM Fabiano Caruana in their eighth-round clash.
GM D Gukesh continued his fine form notching up his seventh straight win.
D Gukesh has been in formidable form for India B with a 6/6 on the top board.
Team USA bounced back with a narrow win over Israel.
India A beat Greece 3-1 while the B team trounced Switzerland 4-0 in Chennai
India will field four teams, two each in the Open and Women's sections.