Nandini/Nimboli wants acceptance and it is acceptance by her family, acceptance from her mother who she thinks has abandoned her and she wants her own bapusa whom she finds fault with for not visiting her.
Mangala Urmi and Kamili's problems are way different from Nandini/Nimboli. For them Akheraj is the biggest problem
For Nandini/Nimboli taking on Akheraj and Kundan is not a problem .She can take care of her problems put in front of her by Akheraj and Kundan. If she gets help fine even if she doesn't she does what ever she thinks is the right way to handle them she will do it.Success and failure don't matter to her wrt Kundan Akheraj.
Mangala Kamili and Urmi and their acceptance doesn't make much of a difference to her and it doesn't take care of her emotional need.Mangala told her that she is all that she needs but that has not really lessened her need for her mother
Shivam accepted Nidhi as his sister but that doesn't take away his need to have a Rakhi tied on his wrist by his own sister.
Anandi finds solace in her social work and finds meaning in life by helping others but that doesn't lessen the need to have her daughter with her.
What Nandini wants is way different from what Mangala Urmi and Kamili want.
Just like Anant can't help Anandi with Nandini Mangala Kamili and Urmi can't help Nimboli what she wants.She wants acceptance from Akheraj family because she thinks she is married to Kundan not for any other reason.