For purposes of this section, "nonconforming structure" and "nonconforming lot" shall mean the same as defined in the Municipal Land Use Law.

Any nonconforming use or structure or any lawful use on a nonconforming lot may be continued on the lot or in the structure so occupied. Nothing in this section shall be deemed to constitute a waiver of a violation of any zoning regulation heretofore adopted or to make lawful any unlawful nonconforming use, structure or lot.

No nonconforming use nor structure containing a nonconforming use shall be enlarged, extended, reconstructed or structurally altered except that such structure may be structurally altered to correct an unsafe condition. A nonconforming structure or a structure containing a nonconforming use or located on a nonconforming lot may be restored or repaired in the event of the partial destruction thereof if such destruction does not exceed 65% of the assessed value of such structure immediately prior to such partial destruction.

A nonconforming structure or a structure on a nonconforming lot may be enlarged, except as to height, provided that:

An existing open porch shall not be enclosed if such porch violates the setback or yard regulations of this chapter.