Zidane is a great coach now. He is very experienced. Manchester United will be very lucky if they get Zidane as their coach. But I'm not sure if Zidane would be interested in coaching Manchester United right now.
In order to see Zidane at Manchester United, something has to change dramatically and even Mourinho couldn't make that happen, so I doubt Zidane can. As long as the club's management doesn't change, Man Utd will continue to play bad football and Zidane is not stupid. He has good statistics and it would be too risky to worsen them at Man Utd.