First off, Donny Cates said there will be a definite winner. And some promotional write ups said that "after 60 years they will now settle who is the strongest avenger".
This is just pure speculation on my part because we haven't even seen any preview pics, but there are things in the promo that makes it seem like the victory is leaning towards the Hulk.
First, the fact that they said that the crossover will settle on who is "the strongest avenger" means it has to be the Hulk, because his thing has always been "the strongest one there is".
Second, the Hulk gets top billing in the title. "Hulk vs Thor" (Hulk's name is first). "Banner of War" (as in Bruce Banner).
Third, the list of the 5 issue crossover has been released already and it will end in a Hulk comic book. Why would Hulk lose in his own comic book?
Hope you're wrong but fear you're right.