No new technique they have only showed new Techniques when they are pushed absolutely too the limit it looks bad after all that training soon as they got into the New World they struggle.
But anyway this arc mirrors Alabasta having Luffy brother there, SuperNova basically running the country, Both are Bookers ( Underground Dealers ) Both planning too destroy the country as a plan. Helpless Princess a Civil War basically.
If you remember in Alabasta they havent used any new techs will except from Nami upgrade it will just be an awesome battle but not nearly as good as the other fights