The Christian God, at least here in the USA, is occasionally referred to as "The God of Second Chances". It isn't the typical way of addressing God, but you'll hear it sometimes in the context of talking about somebody who has presumably screwed up their life somehow. There are even a few books floating around by that name.
Whatever his personal beliefs, Sanford's district he represents is heavily Evangelical Christian, so whenever possible he tries to make his public statements using language his Evangelical voters will identify with.
Typically you will hear Christians say "a God" when they are trying to contrast the God they believe in with the version of God other people (even perhaps other Christians) believe in.
At first blush, the statement doesn't make much sense if you think of God as the one-and-only God that exists in the universe, as Christians supposedly do. However, Evangelical Christians tend to place an emphasis on everyone having their own personal relationship with God.
So basically what he's saying (assuming he said "A God" rather than a "The God" which you misheard), is most likely something along the lines of "The God I (and probably you folks too) believe in", while the "of Second Chances" is referencing a popular conception amongst his district's voters of God in the context of forgiveness.