So you think of the nickel as fuel and not a required catalyst for the reaction?
If the Ni is a fuel then it would be consumed or transformed by the reaction. That would
greatly change the calculations about nickel being cost effective.
I think of everything in the inner chamber as 'fuel'. And there is a lot more there than Ni/H. Further to your point, if Nickel was 'consumed' then we would need very little of this common element to power the planet for a few millenia- E=mc2 is, after all, a very large number. And if it was 'transformed' the transformed products might be as valuable or more valuable and useful than the initial metal - or if there is merely a shift in the isotopic ratio, then there would remain all the more usual uses of Ni for the ash. So no worries there.