The 26-year-old Chopra was at fourth spot till the fourth round before sending his spear to 85.58m in his fifth attempt.
He saved the best for the last as his sixth and final attempt measured 89.49m.
Two-time world champion and Paris Olympics bronze medallist Anderson Peters of Grenada won the event with his second round monster throw of 90.61m while Julian Weber of Germany took the third spot with 87.08m.
Nursing a long-standing groin injury, Chopra claimed a silver in the Paris Olympics on August 8 with a 89.45m throw, having won a historic gold in the Tokyo edition of the Games three years ago.