I don't think Chase will kill Tony off, for personal as well as practical reasons.

First the personal: I think it's clear that although Chase is not a gangster, he clearly sees Tony as himself. From the beginning he's stated that the relationship between Tony and Livia was based on his own mother and himself. I just don't think he can bring himself to do it.

As for the practical reason: I don't care what he says about this being the end. If 5 or 7 years from now he's offered a ridiculous amount of money to do a movie or even a 6 hour mini series for HBO, he's gonna want to do it.

If he kills off Tony, he closes that door forever.