I love 616 Nick, but buying an 80 year old who could still kick ass like that would be difficult. Unless it was Clint Eastwood playing. Then there would be no problem.
One way around it would be to show that Sam Jackson is 616's grandson or some bullshit like that.
616 Nick Fury downed a prototype immortality serum at some point. It didn't stop his aging, but slowed it down to such a degree that Marvel won't ever have to worry about updating him.