Breivik was lone wolf whose ideology came from the internet based “counter-jihad” movement. He was not part of mainstream European nationalist movement. They don’t want anything to do with him.
What we will see more of is nationalist paramilitary groups taking control of local areas and expelling invaders, as happened several times recently in Italy.
I hope your right, my fear is that there will be a “Breivik”, perhaps even working on the side of ISIS who will do this to garner even more sympathy for them. ISIS won’t care about sacrificing a few hundred for the cause.