Often considered the worst Legendary in the game, Nobel has few uses without requiring specific champion pairings. His main use right now is to empower Ninja who is a very strong legendary to give him more stats. That being said, he does have some value if you pair him with a champion who can provide reliable Fear such as Ma’Shalled. His kit is designed to be a monster Turn Meter manipulator but its all dependent on attacking fear targets.
In Patch 5.30, Nobel received some buffs to help lift him out of the doldrums of the vault. His A3 will now decrease 50% of an enemies turn meter instead of 20% whilst his passive will place a True Fear whenever a Turn meter is depleted. His base speed was also increased to be more in line with other champions. Overall this is a step in the right direction but it does not remove the need for that secondary champion. He will however slow the enemies down significantly more than before.