I have used nose clips for the 35 years - all the time practice and racing. I have never had one come off which leads me to believe the problem may be the kind of nose clip you are using. The best ones to use are those used by synchronized swimmers. There are other kinds, but this style is the best. Googling "synchronized nose clips" returns alot of info. Don't bother with the Speedo comfort ones - they will come off. The Finis ones may be ok, but look a little weak for tension and contact with the nose. BUT, I have never used them, so that is just my opinion. The ones I reference in the link above are the ones my wife - 60 years of synchro experience uses - and I used exclusively..
