I feel your pain. Kaiser is 8 months old and we are working through similar issues.
I'm far from a role model for dog training or handling. I however do have one nice advantage: 2 mature Boxers who 'help'.
First thing Kaiser has taught me is that I have to be really consistent in my behavior and commands. Getting him setup to go on a walk was a battle and a game of tug-o-war. I have it mostly fixed now b/c I've been really strict about how we setup to go for a walk. If he doesn't do it the way I want he stays home and I walk Hawk and Sparkles instead. I doesn't like that.
I'm also avoiding trying to do too much too fast. I fully expect getting Kaiser trained to be the way I want is going to take until next summer.
I don't know how long you've had Nala, but be patient with her. She's still mostly puppy. Set things up where she can't fail and focus on building a strong bond between the two of you. The rest will fall in place over time.
My two Boxers are awesome in my opinion. They're easy going, friendly dogs that are fun to be around. I have no idea how I got them that way, it certainly wasn't because I'm a great dog trainer. So relax and enjoy your puppy.