Prior to joining NSE back in 2022,[3][4][5] he was the Managing Director and Chief Executive Officer of the Bombay Stock Exchange (BSE)[6][7] for 10 years.

Chauhan was a member of the core team that founded the NSE, and responsible for setting up their equities and derivatives markets from 1993 to 2000.

[16] In addition, he was instrumental in setting up initial Information Technology infrastructure including the first commercial satellite telecom network in India for NSE.

Under his guidance, BSE has taken leadership position in setting up Small and Medium Enterprises (SME) Platform, Offer for Sale (OFS), Mutual Funds Distribution through Exchanges, e-IPO etc.

Under Ashish's leadership and vision, in 2012, BSE became the first Exchange in the country to launch a dedicated SME platform for listing of Small and Medium Enterprises (SMEs).

[29] India INX is the first exchange to introduce a single platform across multi-assets, equities, commodities, currencies and interest rate derivatives.

It is also the first exchange to launch gold options In January 2017, he successfully completed the IPO of BSE which was pending for over 10 years.