the MCU Nick Fury is based on the character from Marvel's Ultimates universe, not the original prime universe. The characters are very different, with a few similarities.
Did you know that Marvel originally wanted SLJ to play Nick Fury in the MCU? That's why they created the Ultimates universe Nick Fury with Sam's face on it to begin with.
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Funnily enough, the Ultimate Nick Fury design was based on Samuel L Jackson (with permission from thr actor). When they were filming the first Ironman Marvel Studios approached SLJ to see if he would be interested in playing the role in the ppst credit scene, which was very meta because in the Ultimates comics Nick Fury said he would want SLJ to play him in a movie!
The Marvel's Ultimate universe Nick Fury is based on SLJ but he actually didn't know about it until he walked into a comic book store at saw his face staring back at him. Once he called Marvel asking them "what the f**k is going on here" and why his handsome face is on a Marvel comic without his knowledge or approval, Marvel told him that they were making movies based on the comics and that they wanted him to be a part of it, which he agreed. Marvel pretty much created the comics to see how fans would react to SLJ's Nick Fury and got really good feedback even from the man himself.
I've always loved SLJ as an actor since I've first seen Jurassic Park and Pulp Fiction. Him being a huge comic book nerd and an awesome guy, it's a great feeling seeing him on the MCU