Well, giving the scarcity of royal titles in Italy, the best is to focus on Naples.
There's precedents of popes giving this royal title in case of political issues, and with Borgia sitting on the pontifical throne, it shouldn't be that hard if the occasion present (if really obvious nepotism on an unseen scale).
Let's admit Valois do better on Italy, finally managing to hold Milan and Piedmont, and are able to secure a Pontifical-French alliance, but that Valois also accept to renounce their claim on Naples : maybe in exchange of recognition of northern conquests, as well than Cesare Borgia abandoning its pretentions in Romagna to accept leading a buffer state between France and Spain.
It's a bit far-fetched, not likely going to last long, but that's the best overlook I could find.