If you are on a budget, you might not find a dedicated "VST," but you can find high-quality files.
Traditional Indian scales don't always fit into the Western 12-tone tuning. The best plugins allow you to adjust the tuning of individual cents.
You will have to do a lot of manual "pitch wheel" work to make it sound realistic, as it lacks the advanced scripting of paid plugins. What to Look for in a Nadaswaram Plugin
They focus on "human" imperfections. Their Nadaswaram samples include the "breathiness" and the aggressive attack that defines the instrument.