Affordable housing is a permitted use in every residential zone and a conditionally permitted use in every nonresidential zoning district to the extent that production of affordable housing units is mandated by this section. Mandatory on-site production of affordable units shall not increase the density permitted in any residential district. The applicant must satisfy the affordable housing requirements within the existing density. In nonresidential zones, the residential density shall be the minimum required by COAH to satisfy the COAH obligation.