Design courses are relatively new at Nirma University. Quite naturally, you will have some of the inexperienced faculty. With this, everything comes down to how eventually, there is nothing you can learn from here.
When it comes to Srishti School of Design, it is still better as it is an old and quite a reputed institute. It becomes more reliable in front of the masses' perception. However, the school has been sold off to Manipal University. It is now offering degree programs but in this process, course pattern along with the reputed faculty has been put at stake. They are not as well known as they used to be.
You can instead opt for WUD Sonipat and MIT Pune as both of them are good in terms of quality education. Trust me and look into these institutes as well. Make sure eventually your decision is an informed one.