Even i would say the same thing. Go for Nirma, cuz i feel it has a better brand name and is also a very progressive institute.Not saying that welingkars isnt one but atleast we don't see Nirma indulging in hype and stuff. Also i feel, the placements are better in Nirma, cuz i have heard that the placement figures given by Welingkars are inflated. And last but not least, you get an MBA degree if u go for Nirma.
Happy Decision Making
cheers