Samuel L Jackson plays Nick Fury in the movies. Nick Fury is a spy and the leader of SHIELD, he does not have any powers.
Mr. Fantastic is a character from the Fantastic Four who has the power to stretch his body, he is not in any of the Marvel made films because another movie studio owns the rights to Fantastic Four.
You might be confusing the two characters because in the comics they both are middle aged white men with gray hair on the sides, but they are not the same at all.
--
I'm "kind of a big deal".
http://img.imgcake.com/cyclo/Cyclopngegpngre.png