Why does british colonist would have worried about the growth of new france

If New France was too big, they might rebel against the British Colonist and overpower the British. 

United states v.  nixon, 418  u.s.  683 (1974),  was  a landmark  united states supreme court case  that resulted in a unanimous  decision  against president richard  nixon, ordering him to deliver tape recordings  and  other subpoenaed materials to a  federal  district  court.