Welcome to the forum k2hotaling. The puppy is just being a puppy, if they're not sleeping, they want to eat or play. The nipping is normal but the pup needs to learn to stop when told by you or told by the other dog.
Try keeping the dogs separate and spending time with the pup trying to wear it out some. Play fetch, tugging, short walks (long walks when it's older). Give it some mental challenges like finding the treat or one of it's favorite toys etc. The object is to wear it down so it is more cal. Then don't force it but let the two dogs find each other and supervise like you have been. You have every reason to fear fighting and should always be watching for signs of it.
Puppy classes are a good idea and keep firm on who is boss. These are head strong dogs and you have to be even more so.
Now, what is your new girls name and we all like pictures here. How about sharing some or lots with us. I wish you many happy years together.