The best thing you can do is to introduce them on neutral ground. Don't bring the puppy home to Nila's terrotory and then expect them to get along. This is the biggest mistake people make.
Introduce them at another person's house and keep a leash on both of them so you can control the situation. Don't force them around each other, let them scope it out and associate with one another when they're ready.
If she starts showing signs of aggression, get her attention and tell her no. If she shows interest and is polite praise her and give her something yummy (cheese bits?). The trick is to make it a positive situation.
Also, don't leave them alone together for awhile until you're sure they can be trusted. You need to make sure that the puppy knows how to leave Nila alone too. Nila wont always be the one at fault when things get rough.
Also, make sure you have 2 of everything. 2 bones, 2 toys, 2 blankets etc. Keep in mind, they'll be like kids. If one has a different toy, the other will want it. :)
Off topic, but have you taken Nila to obedience training? It may be something you want to do. Even if you have, why not try a course to brush up. You can also look into some different collars (prong collars and such) for more control when you're around other dogs.
Hope I helped somewhat. I know I rambled. If you have any questions, feel free to email me and I'll try to answer :)
And congrats on the puppy!