It is the express intent and purpose of this chapter that if a nonconforming building, structure, sign or use of land was expanded or extended to the limits of expansion for a nonconforming building, structure, sign, or use of land as authorized by a prior zoning regulation or ordinance, said building, structure, sign, or use of land shall nonetheless be authorized to expand according to the provisions of this article in the same manner as are buildings, structures, signs, and uses made nonconforming by the adoption of this chapter.