Your challenge is to have the Union Nationale be a major party in Quebec in the present day with a POD between 1945 and 1959.
What kind of neoliberal? Thatcherite or Reaganite?You don't need that early a POD. Just have Daniel Johnson pere not die in October 1968. He will steadily absorb soft independantiste sentiment into the UN, as was occurring by the time of his death IOTL. The Liberals get squeezed into status as an Anglophone-Allophone third party and eventually dissolve. There will be two parties: an unambiguously neoliberal, socially centre-right UN and a socially progressive/social democratic PQ.