Is Nala a good mother?

For what the film shows, yes:
- She told Kiara to listen to her father in an important matter
- She encouraged Kiara's self-esteem in hunting matters
- She adviced Kiara's father to not make hasty decisions related to Kiara's well-fare
- She was at alert when Kiara was in danger and her father going into rescue (at the end with the cliff and the river)

she is a very good mother she treats kiara as a dauther as she is doing a great job of what she is spose to be doing with simba a mother and a father

With Fluffy, we don't know as much.
With Kiara, yes. As we know Fluffy is Kiara, Nala is very nurturing and loving mom. She's cares very much about Kiara, when it come to dangers. She tells Simba that
she'll be alright while Kiara is exploring adventure. While Simba is worried as heck sending Timon and Pumbaa to look after her.

Well of course, Even though we really didn't see her in TLK 2, We would know she would still be a good mother in TLK 1 So of course nala would take care of her cubs and worry for them like simba would do, If she had a bigger role in TLK 2 I would like to see her have more roles like she had in TLK 2 So nala would be a good mother. Nala is a great lioness.