She can wait to strategize with them. Much as she dislikes waiting to go kill Moord Nag, she wants her takeover to be neater much more. If she can smoothly take over without causing many ripples or causing her neighbors to think it's a good idea to go take her on, she can devote more attention to digging wells and creating a stable country, which will ultimately save more lives in the long run. Sorry, people that get eaten by Moord Nag.

Though it does depend on how long they'll take for it. Are they going to take too long?