We have a five month old Boxer that is in his teething stage and is nipping at my daughter. He has all teeth. Major age

What you are encountering is the beginnings of a dominance conflict in your home. This is common at about 6 months of age when a dog reaches "sexual maturity." The solution is what is called the "no-free-lunch" philosophy of dog training or what is called "deference" training. Major thinks he is an Alpha dog in the home and that must stop. Immediately, read the following link. From this moment onward, Major gets NOTHING before he does something for you (or your daughter, if she is older than 5). He must SIT before any food, attention, etc. He must NO longer be allowed on any furniture (including all beds, couches, and chairs) as that is a position of dominance in the home. Read and follow the advice in the link. Hope this helps.

https://bppethospital.com/wp-content/uploads/2020/09/Basic_Training_Techniques.pdf

do not use any sort of physical reprimand... it will not help.

I see you haven't had a chance to get back to me but given what information you did provide, I believe this might be the information you are looking for. If this isn't what you were looking for or isn't helpful please feel free to come back and we can continue this conversation.

I hope you found this answer to be of some assistance. Enjoy the rest of your day.