Why Sulphuric acid and hydrochloric acid are more widely used comparing wit Nitric acid?
Not sure this is true because there are some processes that use a lot of nitric acid. If it is true, then there could be several explanations. It could be that nitric is more expensive so many of the applications that could use nitric don’t because of cost. It could also be that H2SO4 and HCl are used in processes that are commercially performed in much larger volume than HNO3. Do some of your own research.
