A Mullah regime in power in Iran with no nukes is the ideal situation from India's interests POV.
There are 3 scenarios how this can play out-
1) If America does a regime change and succeeds, the new leader whoever it be will be pro-US and projects including the North-South Transport corridor connecting India to Russia via Iran will be in jeopardy.
2) If Iran gets nukes, it'll be bad. No Muslim country even ones that are friendly to us should ever have nukes. Yeah the current generation of leaders might be friendly to us but there's no guarantee that the next gen won't be Islamist monkeys. This applies to all Islamic nations including UAE.
3) Iran's nuclear capabilities get destroyed and the mullah regime continues to rule without nukes.
For India, scenario no 3 is by far the best. Both 1 and 2 are bad for us in different ways.