I wouldn't look very deep into this at all. He is a rookie playing behind a suspect O line that has struggled specifically in run-blocking. He is still getting up to NFL speed and I expect he will get better, but he does give us something we really need..a break for CMC.
It's a tough gig. Neither guy is getting great blocking... almost every carry Chubba had today, the Saints were already in the backfield when he got the handoff. CMC generating the offense he is with this line is a testament to both his experience and his talent/skill. Chubba is a different style runner, and as a rookie, the line isn't allowing him to play to his strengths, at all.