After his win over Ernis Uulu Ruslan of Kyrgyzstan, the 16-year-old Indian boxer is now assured of at least a silver medal in the tournament.
Chauhan, who made his place in the semi-finals after beating Nozimov Mumin of Tajikistan in the quarters, was in top form against Ruslan and did not give the local boy an inch.
Chauhan is a silver medal winner at the 2012 Sub-Junior National Boxing Championship.
He will stake a claim for the yellow metal in the championship round against Ilyubayev Azat of Kazakhstan on Sunday.
The Indian camp, however, suffered setbacks in the quarter-finals of the pin weight and the bantam weight division.
Reigning sub-junior national champion Mohammad Wasique (46kg), who beat Mongolian boxer Narantsogt to make it to the last eight, came up short against local lad Nursultan Bekbolat. Thounaojam Bickychand's campaign came to an end at the hands of Kholdarov Ikboijan of Uzbekistan.