They sell NPT thread repair kit's,

https://www.mscdirect.com/browse/tnpla/94204013?cid=ppc-google-New+-+Threading+-+PLA_seJ7a6JRI___164110843911_c_S&mkwid=seJ7a6JRI|dc&pcrid=164110843911&rd=k&product_id=94204013&gclid=EAIaIQobChMI_M2v04P63QIVEdbACh3AJAK6EAQYAiABEgLNY_D_BwE