Completely untrue. The Marvel Ultimates Universe has always had a black, Samual L. Jackson looking Nick Fury. Originally it was done without likeness rights, but Marvel approached Jackson about it and he agreed to let them to continue to use his likeness for Ultimate Nick Fury on the condition that he be given first shot at playing him in any movies featuring him from then on. They agreed and that's how it was until Iron Man and he officially became the actor of Nick Fury.
Or to put it simply, Nick Fury was black for years before SLJ portrayed him in the movies and he's black in the main universe now (As Nick Fury Jr. but they drop the Jr.) too because basically everyone associates him to being Nick Fury. The white Nick Fury is ether retired or in deep cover or some shit.
You want a better example of race change in a Marvel movie? Heimdall in Thor or the Kingpin in Daredevil (Affleck).