“‘But are you sure that there is anything to be gained by killing the people?’
[…]
‘Everything. When there were no people in the bungalow, did we have any mongoose in the garden? So long as the bungalow is empty, we are king and queen of the garden; and remember that as soon as our eggs in the melon-bed hatch (as they may to-morrow), our children will need room and quiet.’”
Rikki-tikki overhears this exchange between Nag and Nagaina while they sneak into the bungalow. Here, Nag asks his wife if it is necessary to kill Teddy and his family and Nagaina replies that it is, thus characterizing Nagaina as being just as bloodthirsty as, if not more than, her husband. Her response anticipates Rikki-tikki’s prediction that Nagaina will be “worse than five Nags” later in the text.
“Give me the egg, Rikki-tikki. Give me the last of my eggs, and I will go away and never come back.”
Readers will never know if Nagaina is telling the truth here because Rikki-tikki kills her (and presumably the last egg) shortly after. It’s entirely possible Nagaina means what she says; over the course of the text, she consistently prioritizes the safety and survival of her family over everything, and her hatred of Teddy’s family and of Rikki-tikki is a result of the danger they pose to her eggs. This devotion complicates the reader’s perception of Nagaina as an antagonist and renders her a somewhat sympathetic figure.